Working for a dustbath: are hens increasing pleasure rather than reducing suffering?

Dustbathing is one of the major behavioural systems of domestic fowl that is constrained by commercial caging systems. Although research conducted over the last 20 years has revealed a great deal about causation of dustbathing, attempts at measuring the importance to hens of having access to dustbathing substrate have proven difficult. Various economic techniques, operant conditioning and learning trials have been used to determine whether hens have a 'need' for dustbathing substrate or 'think' about dustbathing in the absence of substrate. In this study, we measured hens' willingness to work to obtain substrate for dustbathing using a vertically swinging door to which weights could be added. Hens were trained to push through the door to enter a goal box containing peat moss. The hens were subjected to two series of trials to compare the maximum weight that they would push to open the door when living in a cage and deprived of dustbathing substrate, with the maximum weight that they would push when living in a pen furnished with litter and a dustbath (non-deprived). Of the 10 hens that opened the door for access to peat moss, six hens pushed more weight when deprived, three hens pushed more weight when non-deprived and one hen pushed an equal amount of weight. Overall, the hens tended to push more weight (860+/-95.6 vs. 682.5+/-83.3 g; P<0.10, one-tailed paired t-test) and tended to make more attempts to open the door (P<0.10) when they were deprived than when they were non-deprived. Significantly more trials resulted in dustbathing when hens were deprived (P<0.01) suggesting that following deprivation, the hens were, in fact, more motivated to dustbathe. The results of these trials indicate that although deprived hens may be more motivated to dustbathe, and that most hens may be willing to work to obtain a dusty substrate when they can see it, they are not necessarily willing to work harder when they are in a state of deprivation than when they have recently dustbathed. These results are very difficult to explain using a 'needs' model of motivation in which deprivation leads to a state of suffering. They are much more consistent with an 'opportunity' model of motivation in which performance of the behaviour, when the opportunity presents itself, leads to a state of pleasure.     

Effects of separation of resources on behaviour of high-, medium- and low-ranked hens in furnished cages

In our previous studies, we demonstrated that dominant hens had priority in using the dust bath, resulted in increased competition for the resource. It seemed that the problem was that the resource was placed on one side of the cage (‘localised’). Therefore, we designed a medium-sized furnished cage with a dust bath and nest box on both sides of the cage (‘separated’, MFS). To evaluate the effects of separation of these resources, we compared the behaviour of high-, medium- and low-ranked hens in MFS cage with that in small (SF) and medium furnished (MFL) cages with a localised resource. In total, 150 White Leghorn layers were used. At the age of 17 weeks, the hens were randomly divided into three groups and moved to small furnished cages (SF, 90 cm wide; five birds per cage) and two types of medium furnished cages (180 cm wide; 10 birds per cage) with a nest box and dust bath on both sides (MFS) and a nest box and dust bath on one side of the cage (MFL). The total dust bath and nest box areas per hen were same for the three cages. The dominance hierarchy was determined by observing the aggressive interactions and by this high-, medium- and low-ranked hens in each cage were identified. The behaviour, use of facilities and physical condition of these hens were measured. Data were analysed by using repeated measure ANOVA. A significant interaction between social order and cage design was found in the proportions of time spent in the dust bath and on performing dust-bathing (both P < 0.001), and these proportions tended to be higher in higher-ranked hens in SF and MFL. Conversely, the MFS low-ranked hens tended to use the dust bath more than the SF and MFL low-ranked hens. Thus, hens from each rank used the dust bath equally in MFS, though the MFS high-ranked hens tended to use the resource less than the SF and MFL high-ranked hens. While the frequency of pre-laying sitting was lower among low-ranked hens (P < 0.05), the proportion of time in the nest box was higher among low- than high-ranked hens (P < 0.01). The low-ranked hens spent more time performing escaping, moving and standing in the nest box. In conclusion, it is suggested that separation of the dust bath to two locations would be an effective arrangement to promote more equal usage of the dust bath by hens from each rank in the furnished cages. It was also confirmed in the present study that nest boxes were not only used for laying eggs but also as a refuge by lower ranked hens.     

Responses to land cover and grassland management vary across life‐history stages for a grassland specialist

Grassland birds have exhibited dramatic and widespread declines since the mid‐20th century. Greater prairie chickens (Tympanuchus cupido pinnatus) are considered an umbrella species for grassland conservation and are frequent targets of management, but their responses to land use and management can be quite variable. We used data collected during 2007–2009 and 2014–2015 to investigate effects of land use and grassland management practices on habitat selection and survival rates of greater prairie chickens in central Wisconsin, USA. We examined habitat, nest‐site, and brood‐rearing site selection by hens and modeled effects of land cover and management on survival rates of hens, nests, and broods. Prairie chickens consistently selected grassland over other cover types, but selection or avoidance of management practices varied among life‐history stages. Hen, nest, and brood survival rates were influenced by different land cover types and management practices. At the landscape scale, hens selected areas where brush and trees had been removed during the previous year, which increased hen survival. Hens selected nest sites in hay fields and brood‐rearing sites in burned areas, but prescribed fire had a negative influence on hen survival. Brood survival rates were positively associated with grazing and were highest when home ranges contained ≈15%–20% shrub/tree cover. The effects of landscape composition on nest survival were ambiguous. Collectively, our results highlight the importance of evaluating responses to management efforts across a range of life‐history stages and suggest that a variety of management practices are likely necessary to provide structurally heterogeneous, high‐quality habitat for greater prairie chickens. Brush and tree removal, grazing, hay cultivation, and prescribed fire may be especially beneficial for prairie chickens in central Wisconsin, but trade‐offs among life‐history stages and the timing of management practices must be considered carefully.     

Influence of nest seclusion and nesting material on pre-laying behaviour of laying hens

Provision of nest sites is beneficial for the welfare of laying hens in intensive production systems. The design of these nest sites has a direct effect on pre-laying behaviour. The aim of this study was to investigate the effects of screening off the entrances of the nest boxes with non-transparent flaps and providing nesting or flooring material on pre-laying behaviour. Eighteen individual Hisex brown laying hens and 18 groups of five hens were tested for 2 days in a test cage containing three nest boxes each with a different nesting material (peat, artificial turf and plastic-coated wire mesh). On one of the days the nest boxes were equipped with plastic flaps at the entrances. Pre-laying behaviour was analysed using focal sampling. Both degree of seclusion and nesting material had an effect on pre-laying behaviour of hens. Nest boxes with flaps were visited less frequently but for a longer duration per visit than nest boxes without flaps. Hens spent more time sitting and scratching, and less time standing and moving when flaps were present. Hens also received fewer pecks (group test) when nest boxes were equipped with flaps. Major differences were found between pre-laying behaviour on coated wire mesh compared to peat and artificial turf with shorter duration of nest visits (group test), more standing (group test) and moving (individual and group test), and less sitting (individual and group test) and object pecking (group test) on coated wire mesh. Differences in pre-laying behaviour on peat versus artificial turf were observed for the behaviours moving (less on peat), sitting (more on peat in the individual test) and object pecking (more on peat in the group test).

It is concluded that hens show more settled pre-laying behaviour and more nest-building behaviour in the presence of flaps at the entrances of nest boxes. These results indicate that seclusion of nest boxes with non-transparent flaps is beneficial to laying hen welfare. Differences in pre-laying behaviour also suggest that plastic-coated wire mesh is less suitable as nesting material than peat and artificial turf.     

Incentive Value learning in Domestic Hens

The present experiment investigated whether domestic hens (Gallus domesticus) assign different incentive values to novel food depending on their deprivation state when they encounter this novel food. Firstly, hens were trained to search under wood shavings in a food dish to find a small amount of a novel food. Half of the hens were then presented with the novel food while food deprived, and the other half were presented to it while sated. In the test, all hens were food deprived, and given access to the food dish used in the first stage, filled with shavings but without food. Hens that had experienced the food while deprived spent more time on food‐related behaviours in and at the dish than did hens that had not (pecking at dish, Median 63 vs. 37, p < 0.05). These results indicate that the first group had assigned a higher value to the novel food. The results show for the first time that incentive value learning occurs in domestic hens. This implies that care must be taken when designing choice tests to take into account the animal’s motivational state when it previously encountered the resources being studied.     

Furnished cages for laying hens: study of the effects of group size and litter provision on laying location, zootechnical performance and egg quality

The furnished cage is a new housing system for layers. A current trend in furnished cage design is to increase group size and replace the litter box with a mat provided with litter. An experiment was set up to determine the effects of group size and litter provision on laying performance and egg quality of beak-trimmed ISA Brown hens housed in large furnished cages with more than 12 hens. Six treatments, each of 18 furnished cages (768 cm(2)/hen including nest and litter area) were compared in a 3 × 2 experimental trial: three group sizes (S20 (20 hens per cage), S40 (40) and S60 (60)), with or without feed as litter distributed on the mat of the litter area. The provision of facilities per hen was equal in all treatments. Mortality, laying rate, mean egg weight, feed intake and feed conversion ratio were unaffected by group size over the 53-week laying period, and performance exceeded the ISA production standards. The overall percentage of eggs laid in the nest exceeded 95% except that it was slightly lower in group S20 (92.0% ± 6.4% v. S40: 96.0% ± 3.3% and S60: 96.2% ± 2.7%) leading to a higher proportion of dirty eggs (S20: 1.6% ± 2.2%, S40: 1.4% ± 1.5%, S60: 1.0% ± 1.0%). At 66 to 70 weeks, eggs laid outside the nest had a slightly higher count of mesophilic bacteria on the eggshell (5.0 log CFU/egg ± 0.4) than those laid in the nest (4.8 log CFU/egg ± 0.5) but no difference in contamination was observed between group sizes. Litter provision had no effect on mortality, egg weight or egg quality traits except for a higher proportion of broken eggs in cages with litter (5.3% ± 6.2% v. 4.6% ± 5.7%). Providing hens with feed for litter was associated with a higher laying rate (97.3% ± 3.2% v. 94.8% ± 4.4% at 23 weeks) and an apparent improvement in feed efficiency at the beginning of the laying period (feed conversion ratio based on feed consumption at the trough: 2.18 ± 0.06 with litter v. 2.28 ± 0.09 without litter at 25 weeks). The results of this study showed that a high level of productivity and good egg quality could be obtained in large furnished cages. Further research is needed to assess the impact on hens' welfare and performance of using more economically competitive substrates than feed for litter.     

Welfare of organic laying hens kept at different indoor stocking densities in a multi-tier aviary system. I: egg laying,and use of veranda and outdoor area

Multi-tier aviary systems are becoming more common in organic egg production. The area on the tiers can be included in the net area available to the hens (also referred to as usable area) when calculating maximum indoor stocking densities in organic systems within the EU. In this article, results on egg production, laying behaviour and use of veranda and outdoor area are reported for organic laying hens housed in a multi-tier system with permanent access to a veranda and kept at stocking densities (D) of 6, 9 and 12 hens/m² available floor area, with concomitant increases in the number of hens per trough, drinker, perch and nest space. In a fourth treatment, access to the top tier was blocked reducing vertical, trough and perch access at the lowest stocking density (treatment D6x). In all other aspects than stocking density, the experiment followed the EU regulations on the keeping of organic laying hens. Laying percentage was significantly lower (P<0.05) in D12 compared with the other stocking densities (90.6% v. 94.3% (±0.7)), most likely due to the concomitant reduction in nest space and drinker availability per hen. No systematic effects of density were found on other laying variables (egg weight, eggs laid outside nests, aviary side preferences). Number of hens using the veranda increased with stocking density. Hens primarily used the range near the house (within 50 m) and hens kept at the lowest stocking density and the smallest group size appeared to use the outdoor area more extensively, based on an assessment of vegetation cover (P<0.05). For the measures reported here, the welfare consequences of increased stocking density were assessed to be minor; additional results are reported in the associated article (Steenfeldt and Nielsen, 2015).     

Early rearing enrichments influenced nest use and egg quality in free-range laying hens

In Australia, free-range egg production pullets are typically reared indoors, but adult layers get outdoor access. This new environment may be challenging to adapt to, which could impair egg production and/or egg quality. Adaptation might be enhanced through rearing enrichments. We reared 1386 Hy-Line Brown® chicks indoors with three treatments across 16 weeks: (1) a control group with standard litter housing conditions, (2) a novelty group providing novel objects that changed weekly, and (3) a structural enrichment group with custom-designed structures to partially impair visibility across the pen and allow for vertical movement. Pullets were transferred to a free-range system at 16 weeks of age with daily outdoor access provided from 25 until 64 weeks. Daily egg production at different laying locations (large nests, small nests and floor), weekly egg weights and egg abnormalities were recorded from 18 to 64 weeks old. External and internal egg quality parameters of egg weight, shell reflectivity, albumen height, haugh unit, yolk colour score, shell weight and shell thickness were measured at 44, 52, 60 and 64 weeks. There was a significant interaction between rearing treatment and nest box use on hen-day production from weeks 18 to 25 (P < 0.0001) with the novelty hens laying the most eggs and the control hens the fewest eggs in the nest box. Similarly, from 26 to 64 weeks, the novelty hens laid more eggs in the large nest boxes and fewer eggs on the floor than both the structural and control hens (P < 0.0001). Egg weight and abnormalities increased with age (P < 0.0001), but rearing treatment had no effect on either measure (both P ≥ 0.19). Rearing treatment affected shell reflectivity and yolk colour with the control hens showing paler colours across time relative to the changes observed in the eggs from enriched hens. The novelty hens may have established nest box laying patterns as they were more accustomed to exploring new environments. The differences in egg quality could be related to stress adaptability or ranging behaviour. This study shows that enriching environments during rearing can have some impacts on production parameters in free-range hens.     

Interrupted incubation: How dabbling ducks respond when flushed from the nest

Nesting birds must provide a thermal environment sufficient for egg development while also meeting self‐maintenance needs. Many birds, particularly those with uniparental incubation, achieve this balance through periodic incubation recesses, during which foraging and other self‐maintenance activities can occur. However, incubating birds may experience disturbances such as predator or human activity which interrupt natural incubation patterns by compelling them to leave the nest. We characterized incubating mallard Anas platyrhynchos and gadwall Mareca strepera hens’ responses when flushed by predators and investigators in Suisun Marsh, California, USA. Diurnal incubation recesses initiated by investigators approaching nests were 63% longer than natural diurnal incubation recesses initiated by the hen (geometric mean: 226.77 min versus 142.04 min). Nocturnal incubation recesses, many of which were likely the result of predators flushing hens, were of similar duration regardless of whether the nest was partially depredated during the event (115.33 [101.01;131.68] minutes) or not (119.62 [111.96;127.82] minutes), yet were 16% shorter than natural diurnal incubation recesses. Hens moved further from the nest during natural diurnal recesses or investigator‐initiated recesses than during nocturnal recesses, and the proportion of hen locations recorded in wetland versus upland habitat during recesses varied with recess type (model‐predicted means: natural diurnal recess 0.77; investigator‐initiated recess 0.82; nocturnal recess 0.31). Hens were more likely to take a natural recess following an investigator‐initiated recess earlier that same day than following a natural recess earlier that same day, and natural recesses that followed an investigator‐initiated recess were longer than natural recesses that followed an earlier natural recess, suggesting that hens may not fulfill all of their physiological needs during investigator‐initiated recesses. We found no evidence that the duration of investigator‐initiated recesses was influenced by repeated visits to the nest, whether by predators or by investigators, and trapping and handling the hen did not affect investigator‐initiated recess duration unless the hen was also fitted with a backpack‐harness style GPS–GSM transmitter at the time of capture. Hens that were captured and fitted with GPS–GSM transmitters took recesses that were 26% longer than recesses during which a hen was captured but a GPS–GSM transmitter was not attached. Incubation interruptions had measurable but limited and specific effects on hen behavior.     

Nest Defense by Red Jungle Fowl (Gallus gallus spadiceus) Hens: The Roles of Renesting Potential,Parental Experience and Brood Reproductive Value

Reproductive-effort theory predicts that parents of any given age should expend more parental effort (1) as their residual reproductive value declines, and (2) as the reproductive value of offspring increases. An observational and experimental study of nest defense by captive red jungle fowl hens was used to examine these two predictions. Both young and old individuals significantly increased defense of the second nest compared to the first nest within a season; this pattern occurred for the defense of both eggs and chicks. Old hens showed significantly greater defense of both eggs and chicks in each of the nests than did young hens. Both young and old hens were significantly more defensive of chicks than eggs in each of two clutches of a season. Hens also reduced their nest defense significantly at the end of a two to three-day period after their chicks were replaced with eggs, and increased their nest defense after eggs were exchanged for chicks. Hens given four chicks showed more vigorous defense than hens given two chicks. When the brood size of hens with four chicks was reduced to one chick, the hens responded by exhibiting less vigorous nest defense. These patterns of nest defense in jungle fowl were not confounded by parental experience of hens, or differences in offspring quality that are related to time of breeding, maternal age, sire genetic quality or vulnerability of offspring to weather.     

Ovarian steroid production in vitro during gonadal regression in the turkey. I. Changes associated with incubation behavior.

The mechanism regulating ovarian regression during incubation behavior in the domestic turkey has not been elucidated. This study was designed to determine whether ovarian steroidogenic potential is depressed during gonadal regression associated with the onset of incubation behavior. Hens were housed in floor pens equipped with trap nests that were checked 7 times per day. Hens were grouped, according to nesting frequency and egg production, into the following classifications: laying (laid an egg every day and trapped in the nest only once/day); transitional (laid an egg every day but trapped in the nest 4 or more times/day); and Day 1, Day 3, and Day 5 incubating (no egg for 2, 4, or 6 days, respectively, while trapped in the nest at least 4 times/day). Follicular atresia was evident in the largest preovulatory follicle (F1) in transitional hens, extensive in F1 through the third largest follicle (F3) in Day 1 incubating hens, and extensive in F1 through F7in Day 3 incubating hens. Levels of circulating LH, progesterone (P), androgen (A), and estradiol (E) decreased in transitional hens relative to concentrations in laying hens and remained low thereafter. In contrast, levels of prolactin were greater in Day 3 and Day 5 incubating hens than in laying, transitional, or Day 1 incubating hens. Basal production of P by F1 granulosa cells was lower from Day 1 incubating hens than from the other groups. Production of P in response to porcine-luteinizing hormone (pLH) was greater by cells from transitional and Day 1 incubating hens than from those of laying hens.(ABSTRACT TRUNCATED AT 250 WORDS)     

Residual concentrations of antimicrobial growth promoters in poultry litter favour plasmid conjugation among Escherichia coli

Considering that plasmid conjugation is a major driver for the dissemination of antimicrobial resistance in bacteria, this study aimed to investigate the effects of residual concentrations of antimicrobial growth promoters (AGPs) in poultry litter on the frequencies of IncFII-FIB plasmid conjugation among Escherichia coli organisms. A 2 × 5 factorial trial was performed in vitro, using two types of litter materials (sugarcane bagasse and wood shavings) and five treatments of litter: non-treated (CON), herbal alkaloid sanguinarine (SANG), AGPs monensin (MON), lincomycin (LCM) and virginiamycin (VIR). E. coli H2332 and E. coli J62 were used as donor and recipient strains, respectively. The presence of residues of monensin, lincomycin and virginiamycin increased the frequency of plasmid conjugation among E. coli in both types of litter materials. On the contrary, sanguinarine significantly reduced the frequency of conjugation among E. coli in sugarcane bagasse litter. The conjugation frequencies were significantly higher in wood shavings compared with sugarcane bagasse only in the presence of AGPs. Considering that the presence of AGPs in the litter can increase the conjugation of IncFII-FIB plasmids carrying antimicrobial resistance genes, the real impact of this phenomenon on the dissemination of antimicrobial resistant bacteria in the poultry production chain must be investigated.     

Nest sharing under semi-natural conditions in laying hens

Under natural conditions, the feral hen (Gallus gallus domesticus) will choose a nest location away from the flock, whereas under commercial conditions, the domestic hen will often choose the same nest as other hens have used or are still using. Simultaneous nest sharing causes several welfare problems to laying hens, and egg production may also be negatively affected. Understanding what causes this difference in nest location selection may provide solutions to the problems associated with simultaneous nest sharing. The aims were to investigate whether a commercial strain of laying hens normally housed in intensive production systems share nests under semi-natural conditions and to describe the behaviour if this behaviour occurred. Twenty 15 weeks old hens were released into an 840 m² enclosure with multiple options for natural and semi-natural nest sites. Over a 63-day period records were made daily of each nest with regard to number of eggs, position, and materials used. On five mornings nesting behaviour was observed. Nest sharing occurred on all but the first 5 days of egg-laying. The majority of hens (n = 14) chose to visit an occupied nest at least once, but no hens exclusively used occupied nests. Visits in shared nests lasted longer than visits in undisturbed nests (13 min 50 s (±4 min and 57 s) vs 30 min 44 s (±4 min and 55 s); P < 0.001). Fifteen nests were used. All shared nests (n = 5) were placed up against the borders, whereas the majority of non-shared nests (n = 7 out of 10) were placed more than 1 m away from the borders (P = 0.002). Some results indicate that nest sharing was caused by environmental restrictions.     

Timing,frequency, and duration of incubation recesses in dabbling ducks

Nest attendance is an important determinant of avian reproductive success, and identifying factors that influence the frequency and duration of incubation recesses furthers our understanding of how incubating birds balance their needs with those of their offspring. We characterized the frequency and timing (start time, end time, and duration) of incubation recesses for mallard (Anas platyrhynchos) and gadwall (Mareca strepera) hens breeding in Suisun Marsh, California, USA, and examined the influences of day of year, ambient temperature at the nest, incubation day, and clutch size on recess frequency and timing using linear mixed models. Mallard, on average, took more recesses per day (1.69 ± 0.80, mean ± standard deviation) than did gadwall (1.39 ± 0.69), and 45% of mallard nest‐days were characterized by two recesses, while only 27% of gadwall nest‐days were characterized by two recesses. Mallard morning recesses started at 06:14 ± 02:46 and lasted 106.11 ± 2.01 min, whereas mallard afternoon recesses started at 16:39 ± 02:11 and lasted 155.39 ± 1.99 min. Gadwall morning recesses started at 06:30 ± 02:46 and lasted 91.28 ± 2.32 min, and gadwall afternoon recesses started at 16:31 ± 01:57 and lasted 192.69 ± 1.89 min. Mallard and gadwall started recesses earlier in the day with increasing ambient temperature, but later in the day as the season progressed. Recess duration decreased as the season progressed and as clutch size increased, and increased with ambient temperature at the nest. The impending darkness of sunset appeared to be a strong cue for ending a recess and returning to the nest, because hens returned to their nests earlier than expected when recesses were expected to end after sunset. Within hens, the timing of incubation recesses was repeatable across incubation days and was most repeatable for mallard afternoon recesses and on days in which hens took only one recess. Hens were most likely to be away from nests between 04:00 and 07:00 and between 16:00 and 19:00; therefore, investigators should search for nests between 07:00 and 16:00. Our analyses identified important factors influencing incubation recess timing in dabbling ducks and have important implications for nest monitoring programs.     

Solid-state fermentation of maple wood by Polyporus anceps

Summary Solid-state fermentations of alkali-treated maple wood shavings were carried out at 30°C in three types of static tray fermenters using Polyporus anceps. Comparison of the fermentation products after 40 days showed a recirculating tower bioreactor (RTB) to be more effective for the production of protein and the consumption of substrate than either a shallow or deep static tray fermentation vessel. Use of the RTB resulted in 70% substrate utilization and a residue containing 17% crude protein.     

Preference for bedding material in Syrian hamsters

This study aimed to determine whether Syrian (golden) hamsters, Mesocricetus auratus, prefer certain bedding materials and whether bedding material can affect paw condition, body weight gain and wheel-running activity. In a first experiment, 26 male hamsters had access to two connected cages, each cage containing a different bedding material (either pine shavings, aspen shavings, corn cob or wood pellets). In a second experiment, 14 male hamsters had access to four connected cages that contained the different bedding materials and also a piece of paper towel to serve as nest material. In a third experiment, 30 male hamsters were each placed in a single cage, 10 of them with pine shavings, 10 with aspen shavings and 10 with corn cob, and they were monitored for 50 days. Significant preferences in the first experiment were: pine shavings over aspen shavings, corn cob over wood pellets, pine shavings over corn cob and aspen shavings over wood pellets (aspen shavings versus corn cob was not tested). However, there was no significant preference expressed in the second experiment, suggesting that the general preference for shavings in the first experiment was based on bedding material suitability as a nesting material. No significant effect of bedding material on paw condition, body weight gain and wheel-running activity was detected. None of the four bedding materials tested in this study can be judged to be inappropriate in the short term if nesting material is added to the cage and if the litter is changed regularly.     

The effects of demonstrator social status and prior foraging success on social learning in laying hens

Opportunities for social learning within a group of animals are likely to be influenced by the social dynamics of that group. Some individuals may be more influential demonstrators than others even when there are no differences in their skill level or performance. In this study of domestic hens, Gallus gallus domesticus, differences in demonstrator salience were examined. From 24 separate flocks we selected as demonstrators a dominant cockerel, a dominant hen, a mid-ranking hen or a subordinate hen. Demonstrators were pretrained to perform an operant discrimination task to obtain food. Six observers from each flock individually watched the demonstrator perform the task for four 5-min sessions held on consecutive days. On the fifth day observers were tested individually in the operant chamber. We analysed data from 19 flocks, where there were no quantitative differences in demonstrator performance. Observer hens of relatively high social status performed more correct operant pecks than observer hens of relatively low social status. Demonstrator category also had a significant effect on subsequent observer behaviour. Hens that had observed cockerels performed very few general pecks or operant pecks. Hens that had observed dominant hens performed more operant pecks, but hens that had observed sub-ordinate hens performed more general pecks in the chamber. The results suggested either that there was an interaction between dominance and gender in demonstrator salience or that dominant hens might have been influential because of some factor imperfectly associated with their dominance status. A possible candidate was the foraging ability of the dominant hens. In a second experiment using the same protocol, we manipulated the prior foraging success of dominant hens from four additional flocks but this had no significant effect on their subsequent influence as demonstrators. Copyright 1999 The Association for the Study of Animal Behaviour.     

Reducing feather pecking when raising laying hen chicks in aviary systems

Aviary systems for laying hens offer several advantages over battery cages. However, pecking the feathers of conspecifics remains a serious problem that negatively affects the welfare of the birds as well as the economy of a farm. From experimental studies with small groups, it has been shown that feather pecking and foraging behaviour are related and that both behaviour are influenced by early access to litter substrate. We, therefore, hypothesised, that feather pecking in aviaries can be reduced with an adequate management in the first 2 weeks of life.Each of seven pens on six commercial poultry farms, was divided into two identical compartments (matched pair design). In one of the compartments (experimental compartment) chicks were reared for the first 2 weeks of life with access to litter (wood shavings, in one case with additional straw), while the chicks in the other compartment (control) were kept on a plastic grid. Thereafter, all chicks had unrestricted access to litter and there were no differences between the two compartments neither in housing conditions nor in management procedures.Chicks in the experimental compartments spent significantly more time foraging (week 5), showed significantly less feather pecking (weeks 5 and 14) and significantly fewer birds had damaged tail feathers (weeks 5 and 14).The study demonstrates that in aviaries, under commercial conditions, early access to litter substrate has a significant effect on the development of feather pecking. In order to reduce feather pecking and to increase foraging behaviour, it is recommended that laying hen chicks raised in aviary systems do get access to litter from day 1 on.     

Factors affecting nest choice by Pekin ducks

To encourage nest use in breeder poultry flocks, it is important that nest boxes are attractive. Few studies have evaluated factors affecting nest attractiveness to ducks. We assessed the effects of nest box experience (Experiments 1 and 2) and features of nests, including degree of enclosure (Experiments 1 and 2) and the presence of an egg (Experiment 3), on nest site selection by sexually mature Pekin ducks. The hens were tested individually in pens containing different nest box choices. Nest preferences were determined based on the locations of 14 successively laid eggs. Ducks in Experiment 1 were provided with nest box access prior to the onset of lay (20 weeks of age, EXP group, N = 12) or at the time of preference testing (35 weeks of age, DELAYED-EXP group, N = 12). Delaying nest box access by 15 weeks did not significantly affect the proportion of eggs laid in nest boxes rather than on the floor (P = 0.40). Regardless of experience ducks laid more than 66% of their eggs in nest boxes offering a higher degree of enclosure. Ducks in Experiment 2 were reared with either open-top (OP, N = 12) or closed-top (CL, N = 12) boxes. Regardless of rearing condition, ducks preferred boxes with the highest level of enclosure offered. Ducks laid twice the expected proportion (25%) of eggs in CL boxes with curtains (P = 0.0004). CL boxes without curtains were used as predicted by chance, 25% (P = 0.746), while OP boxes with (P = 0.009) and without (P = 0.015) curtains each contained only half the expected number of eggs. Ducks in Experiment 3 were provided with two nest boxes, one of which contained the egg laid the previous day. Each day, the newly laid egg was marked and either placed back in the nest box where it was found (HANDLED, N = 12) or moved into the adjacent nest box (MOVED, N = 12). Ducks in HANDLED and MOVED laid 97.6% and 79.8%, respectively, of their eggs in boxes containing the previous day's egg. While ducks in HANDLED were consistent in their choice throughout the test, those in MOVED developed the preference over time (P = 0.039), suggesting that the preference for laying in a nest containing an egg may be influenced by experience. These results indicate that nest box enclosure and the presence of an egg are important in determining the nesting choices of Pekin ducks. Incorporating these features into nest boxes may be useful for increasing consistency of nest use in breeder duck flocks.     

Artificial nest site preferences of Black-capped Chickadees

ABSTRACT.   To facilitate study of the breeding biology of parids, Grubb and Bronson (1995; Condor 97: 1067–1070) designed artificial "snags" made from polyvinyl chloride (PVC) tubes. Because the cost of artificial snags is greater than that of traditional wooden boxes, we examined alternatives to PVC snags for attracting chickadees to artificial nesting sites. From 2005 to 2007, we compared the use of PVC snags and wooden nest boxes by Black-capped Chickadees ( Poecile atricapillus ) in Sapsucker Woods Sanctuary in Ithaca, New York. We also quantified the use of cavities with and without wood shavings. The probability of chickadee excavation was greater (60–70% per yr) in filled snags (with wood shavings) than in filled boxes (40–50%; logistic mixed model, P = 0.01), and chickadees initiated more nests in filled snags (25–30%) than filled boxes (15%; P = 0.03). Chickadees also initiated significantly more nests ( P = 0.03) in filled than unfilled boxes. Although wooden boxes filled with wood shavings were used more often by Black-capped Chickadees than unfilled wooden boxes, artificial snags filled with wood shavings were used most, were no more likely than boxes to be usurped by House Wrens ( Troglodytes aedon ), and were less likely than boxes to be occupied by mice. Thus, artificial snags may be the better option for investigators studying the breeding biology of chickadees.