Persistency of broodiness in recycled turkey hens

Large White turkey breeder hens identified as broody during their initial egg production cycle were recycled into a second and third reproductive cycle in order to determine the persistency of broodiness. Egg production data included time to first egg, duration of lay and the number of eggs per hen. Nesting data included time to first broody nesting activity and duration of broody nesting activity. In general, there were no significant differences among the three cycles for the above observations. Mean values over the three cucles were as follows: 24.6 days to first egg following photostimulation; 49.4 days of egg production; 29.4 eggs per hen; 46.9 days from the first egg to first broody nesting and 59.7 days duration of nesting. Of 10 hens identified as broody in their first egg production cycle and followed through two additional 20-week cycles, seven hens demonstrated broody nesting behavior and nine had low rates of egg production. It was concluded that broody traits of a given hen are carried over into subsequent cycles.     

Changes in endocrinological parameters and production performances in Turkey hens (Meleagris gallopavo) submitted to different broody management programs

Occurrence of broodiness, egg production, feed consumption index and changes in the LH and prolactin levels were compared for turkey hens raised under 3 broody management programs. All hens (n = 60 per group) were regularly ejected from the nest (basic treatment). Moreover, one group of hens was also rotated weekly (partial treatment), while in the third group (full treatment) hens showing broody symptoms were also identified daily and isolated for 24 hours. The percentage of hens which were identified as broody at least once was similar under the 3 programs (30%), although the use of the full and partial programs were more effective in inducing the disruption and/or preventing further expression of broody behavior. Plasma LH concentrations decreased progressively throughout the reproductive cycle under the 3 treatments. Maximum plasma concentrations of prolactin were measured between the 5(th) and the 10(th) weeks of production; higher concentrations of prolactin were maintained for a longer period under the full treatment, while a lower amplitude rise in plasma prolactin concentrations was observed in the hens submitted to the partial treatment. The egg production and feed consumption indices were lower and higher, respectively, under the full treatment than the basic treatment and partial treatments. We conclude that management programs need to be carefully evaluated under commercial conditions not only with respect to broodiness expression but also to egg production.     

Increased synthesis of prolactin and growth hormone during incubation in the pituitary of broody Nagoya hens

Synthesis and release rates of prolactin and growth hormone (GH) in the anterior pituitary of laying and incubating broody chickens (Nagoya breed) were determined by a disc electrophoretic technique after in vitro incubation of anterior pituitaries with a labeled amino acid. Prolactin synthesis and release were two-fold higher in incubating than in laying hens, resulting in twofold increase in the concentration of prolactin in the gland. GH synthesis was three-fold higher in incubating than in laying hens but GH release was not affected by the incubation. GH concentration in the pituitary gland also increased in incubating hens. It is suggested that these changes in hormone synthesis, release, and concentrations are related to nesting behaviour and nutritional condition of incubating hens.     

Endocrinological and behavioural effects of p-chlorophenylalanine (PCPA) oral administration to broody turkey hens (Meleagris gallopavo)

Changes in plasma levels of prolactin and LH, feed intake, water consumption, behavioural pattern and ovarian activity were recorded after oral administration of PCPA to broody turkey hens. A decrease in prolactin concentration was measured, from day 3, in 3 out of the 5 birds treated with 100 mg PCPA/kg body weight (BW) for 3 consecutive days. In these hens, broodiness was disrupted on day 6 and feeding activity subsequently increased to levels of photorefractory hens. Neither LH concentrations nor ovarian activity were affected after treatment with PCPA. Moreover, PCPA treatment was ineffective at a 50 mg/kg BW dose. These results confirm that a serotoninergic mechanism is probably involved in prolactin release and moreover suggest that prolactin is implicated in maintaining broody behaviour. However, the reductions in the plasma concentration of prolactin induced by PCPA were not sufficient to restore the hypothalamic-hypophyseal-ovarian axis to a physiological status characteristic of the laying hen. Therefore, PCPA does not appear to be a useful method of treating broodiness in commercial turkey hens.     

Influence of Nest Deprivation on Behaviour,Hormonal Concentrations and on the Ability to Resume Incubation in Domestic Hens (Gallus domesticus)

In this study, we investigated the influence of the length of nest deprivation period (3 vs. 6 d) on the ability to renest of incubating hens. We focused on the hens' behaviour, particularly on nesting and calls, on their prolactin, luteinizing hormone (LH) and oestradiol concentrations. Nest deprivation induced a drop of prolactin and an increase of LH plasmatic concentrations in hens. These changes in circulating pituitary hormones were followed by changes in ovarian function: the persistent rise of plasmatic oestradiol gave evidence of the resumption of ovarian activity. After nest deprivation, the number of clucks increased significantly and food calls appeared; these results demonstrate that ‘maternal’ calls can be emitted outside the maternal context. Our results suggest that the onset of typical maternal calling is strongly controlled by internal state such as plasmatic hormonal concentrations, independently of social stimulation. None of the 10 hens deprived for 6 d resumed incubation when given the opportunity, whereas, after a 3 d deprivation period, three out of 10 hens renested and two hens incubated sporadically and then gradually abandoned their nests. Long periods of nest deprivation appear to disrupt the habits of sitting and nesting. Before nest reopening, all the hens presented low levels of plasmatic prolactin. Plasma prolactin concentrations of the renesting hens increased after nest boxes were reopened and returned to levels found in incubating hens. We suggest that pituitary prolactin rather than plasmatic prolactin is responsible for the maintenance of incubating potential in hens deprived of their nests.     

Intracranial prolactin perfusion induces incubation behavior in turkey hens

Intracranial perfusion of ovine prolactin (oPrl) via osmotic pump in laying turkey hens caused a sudden onset in incubation behavior, defined as an increase in nest visits. The hens also displayed a gradual decrease in egg laying during the time they were receiving oPrl, another indicator of the onset of incubation. Circulating immunoreactive turkey Prl levels fell during the perfusion period, even though the hens were displaying persistent nesting activity and reduced egg laying. No effects on serum LH were noted. Perfusion of oPrl during the first 14 days of photostimulation delayed the onset of egg laying by several days. No effects on serum Prl or serum LH were noted. It is suggested that incubation behavior is facilitated by central levels of Prl.     

Endocrine changes in the incubating and brooding turkey hen

Turkey hens were allowed to incubate eggs and to hatch and rear young. Plasma prolactin (Prl) levels increased prior to the start of continuous incubation and rose sharply as incubation progressed to reach a peak of 1178.2 +/- 221.8 ng/ml (mean +/- SEM) just before hatching. Prl levels then fell precipitously before the hens left the nest, and returned to preincubation levels (36.8 +/- 3.4 ng/ml) by the time the poults were 2 weeks old. These results show that the high plasma concentrations of Prl found during incubation are not initiated or maintained only by the stimulus of nesting. We suggest that the decline in Prl levels at the end of incubation could be related to the pipping and hatching of eggs, and the consequent shift to maternal behavior. Plasma growth hormone (GH) levels were significantly increased in hens which were brooding poults, but not in hens incubating eggs. An elevenfold, 1-day increase in plasma GH was observed immediately after the hens left the nests. Mean plasma GH levels rose from 12.0 +/- 4.7 ng/ml on the day that the hens left the nests to 133.0 +/- 32.0 ng/ml on the following day, and then declined to 23.1 +/- 9.6 ng/ml after an additional day. There were no significant changes in plasma thyroxine levels during laying, incubation and brooding. Plasma glucose concentration was significantly depressed during incubation.     

Cardiovascular responses to thoracic skin cooling: comparison of incubating and non-incubating Bantam hens

Summary Body temperatures, metabolic rate, haemostatic parameters, and cardiovascular reactions to thoracic skin cooling were compared between incubating (broody) and non-broody Bantam hens. Under resting conditions, without thoracic skin cooling, cardiac output of broody hens was twice that of non-broody hens. However, their metabolic rate was increased by only one-third over that of non-broody hens, and the arteriovenous difference in oxygen concentration was smaller for broody birds. This indicates a higher rate of non-nutrient blood flow during incubation. A higher thoracic skin temperature (T _ths) for broody hens compared to non-broody hens suggests that brood patches are the probable site of this increased flow through arteriovenous anastomoses (AVAs). Thoracic skin cooling increased metabolic rate and significantly more in broody hens, but did not increase AVA blood flow. The relation between metabolic rate and total peripheral resistance indicated more intense vasodilation for broody hens at the relatively low metabolic rates during moderate cooling, and more intense vasoconstriction for the broody hens at the high metabolic rates during stronger cooling. This corresponds to T _ths measurements indicating dilation of brood patch AVAs with moderate cooling and AVA constriction with severe cooling. During moderate cooling, vasoconstriction in the feet and wattles of broody hens (but not of non-broody hens) freen non-nutrient blood flow for redistribution to the brood patches. Thus, the cardiovascular system of the hen seems to adjust to the special demands of incubation by a permanent increase of AVA flow in the brood patch, and by an additional capacity for brood patch vasodilation induced by cold stimuli in the range from 35 to 25°C. This corresponds well to the temperature range for development of galliform embryos.Abbreviations AVAs arteriovenous anastomoses - BP arterial blood pressure - CaO₂ and CvO₂ arterial and venous oxygen concentrations, respectively - HR heart rate - MAP mean arterial blood pressure - cardiac output - SV stroke volume - T _bs back skin temperature - T _c cofon temperature - T _f foot temperature - T _ths thoracic skin temperature - TPR total peripheral resistance - T _w wattle temperature - oxygen consumption     

Adaptation of homeostatic thermoregulation: comparison of incubating and non-incubating Bantam hens

Summary Incubating and non-incubating Bantam hens were exposed to identical thoracic skin cooling to study the difference between their physiological responses with regard to thermoregulatory adaptation to incubation. Under resting conditions thoracic skin temperature (T _ths) and metabolic heat production (M) were significantly higher in broody than in non-broody hens, indicating a permanently increased conductance of the brood patch. Thoracic skin cooling from 35 to 25 °C decreased T _ths less in broody than in non-broody hens. In broody hens, these coolings induced a large, immediate increase in M, no constriction of brood patch vasculature, and a decrease in colonic temperature (T _c). This decrease in T _c triggered no further increase in M, but induced vasoconstriction in the feet. The coolings induced a smaller increase in M in the non-broody hens, accompanied by pronounced vasoconstriction, and did not affect T _c and foot temperature, T _f. The effects of more severe thoracic skin cooling (between 25 and 15°C) differed much less between non-broody and broody hens. Vasoconstriction of the brood patch also occurred in the latter. It is concluded that in adaptation to incubation the thoracic skin becomes more sensitive, and its input signal becomes stronger for the control of certain effector systems of thermoregulation, allowing a controlled heat transfer to the eggs.Abbreviations BM body mass - M metabolic heat production - T _c colon temperature - T _ths thoracic skin temperature - T _f foot temperature - T _bs back skin temperature - T _stim stimulation temperature - VO₂ oxygen consumption     

Effects of ovariectomy or force feeding on the plasma concentrations of prolactin and luteinizing hormone in incubating turkey hens

The effect of ovariectomy (OVX) on plasma concentrations of prolactin (PRL) and luteinizing hormone (LH) in incubating turkey hens was studied. Neither the sham-operated nor the OVX hens exhibited any change in the pattern of incubation behavior as a result of the surgery. Plasma concentrations of estradiol decreased to less than approximately 3 pg/ml by 2 days after surgery in the OVX hens. There were no significant differences in plasma levels of PRL between the sham-operated and OVX hens throughout the study. The concentration of PRL did not change in either the sham-operated or OVX hens and was maintained at high levels after surgery and during incubation of the eggs. By 2 days after hens were placed into cages, plasma levels of PRL significantly decreased and were maintained at low levels in both groups. The concentration of LH did not change in either group during the two wk after surgery when the hens were incubating eggs. After the hens were placed into cages, the concentration of LH increased in the OVX hens and was maintained at significantly higher levels than in the sham-operated hens. By contrast, the concentration of LH increased within 4 days after OVX of out-of-lay but nonincubating hens. The delay in the postcastration increase in plasma level of LH in the OVX hens was not associated with anorexia of incubating hens, since plasma levels of LH were not affected by force-feeding unless plasma levels of PRI were suppressed by nest deprivation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Prevention of incubation behavior expression in turkey hens by active immunization against prolactin

The consequences of active immunization against prolactin on expression of incubation, reproductive performance and hormonal profiles were evaluated in turkey hens. Hens were injected weekly for 4 wk starting 8 wk before being submitted to a stimulatory photoperiod and 3 times thereafter at intervals of 4 to 5 wk. The hens were injected i.d. with 0.5 mL of a mixture diluted half in Freund's adjuvant. The mixture was prediluted in .9% saline and contained 100 micrograms of a fusion protein (GST-tPRL), GST, oPRL or vehicle. The results indicate that active immunizations with GST-tPRL or oPRL both induce production of specific prolactin antibodies. The onset of egg production was unaffected but higher egg production was observed for the GST-tPRL immunized hens. No GST-tPRL immunized hens expressed incubation behavior, whereas 20 to 30% of hens in the other experimental groups did so. Apparent hyperprolactinemia was detected by RIA for the GST-tPRL immunized groups starting before photostimulation and lasting until Week 10 of egg production but not in other groups. No significant differences were observed in either plasma LH or estradiol concentrations of immunized and nonimmunized turkey hens. In conclusion, both GST-tPRL or oPRL induced the production of antibodies against prolactin in turkey hens. However, only active immunization using GST-tPRL induced higher antibody titers as well as full prevention of incubation behavior expression. Such a pharmacological approach is of great practical interest, although its uses need to be carefully evaluated under commercial conditions.     

Plasma prolactin levels in incubating turkey hens during pipping of the eggs and after introduction of poults into the nest

Plasma levels of prolactin (Prl) associated with incubation and maternal behavior were compared in turkey hens allowed to incubate 10 fertile eggs (Group I, n = 9) or 10 infertile eggs (Group II, n = 7) in open nest boxes. At the end of the day that the first egg hatched, all unhatched eggs were removed from Group I hens and each hen was given 10 poults. At the end of the following day, infertile eggs were removed from Group II hens and each hen was given 10 poults. Although pipping of the eggs changed the incubation behavior of Group I hens, it had no effect on plasma Prl. Subsequent hatch of the eggs and/or presence of poults resulted, within 24 h, in a sharp fall in Prl levels, abandonment of the nests, and a shift to maternal behavior. Visual and auditory exposure to Group I poults had no effect on plasma Prl or incubation behavior of Group II hens incubating infertile eggs in adjacent pens. However, within 24 h after the infertile eggs were exchanged for newly hatched poults, Prl levels in Group II hens declined sharply and the hens abandoned the nests and showed maternal behavior similar to that observed in Group I hens. No significant relationships were found in either group between plasma Prl levels and quality of incubation or maternal behavior.     

Identification of growth-hormone- and prolactin-containing neurons within the avian brain

Prolactin (PRL)- and growth-hormone (GH)-containing perikarya and fibers independent of the anterior pituitary gland have been reported to exist in the central nervous system of several mammalian species. The specific distributions of PRL- or GH-like neurons in the avian forebrain and midbrain, however, have not been reported. The objective of the study was to identify GH- and PRL-containing neurons in the hypothalamus and a few extrahypothalamic areas of two avian species. Brain and peripheral blood samples were collected from laying and broody turkey hens and ring doves. Broody turkey hens and doves had significantly higher plasma PRL concentrations compared with laying hens. Coronal brain sections were prepared and immunostained using anti-turkey GH and anti-chicken synthetic PRL antibodies. In turkey hens, the most dense GH-immunoreactive (ir) perikarya and fibers were found in hippocampus (Hp), periventricular hypothalamic nucleus, paraventricular nucleus, inferior hypothalamic nucleus, infundibular hypothalamic nucleus, medial and lateral septal area, and external zone of the median eminence (ME). In the ring dove, a similar pattern of distribution of GH-ir neurons was noticed at the brain sites listed above except that GH-ir fibers and granules were found only in the internal zone of ME and not in the external zone. In both turkeys and doves, the most immunoreactive PRL-ir perikarya and fibers were found in the medial and lateral septal area, Hp (turkey only), and bed nucleus of the stria terminalis pars magnocellularis. There were no apparent differences in the staining pattern of GH- or PRL-ir neurons between the laying and broody states in either species. However, the presence of GH-ir- and PRL-ir perikarya and fibers in several hypothalamic nuclei indicates that GH and PRL may influence parental behavior, food intake, autonomic nervous system function, and/or reproduction.     

Experience modulates emission of food calls in broody hens.

The aim of these experiments was to determine if previous experience of chicks' response to food calling influences subsequent propension of maternal hens to utter food calls. Seventeen broody hens were tested three times a day without their 3- or 4-day-old chicks. Hens were tested in two situations: chicks were returned either after each test or at the end of all the day's tests. As palatability influences food calling in maternal hens, experiments were conducted first with a highly preferred food item and then with the hens' usual feed. The chicks' capacity to respond regularly to their mother influences the hens' capacity to emit food calls. In fact, although the hens did not lose their maternal state, they uttered fewer food calls when their chicks were removed all day. These results suggest that the chicks' behaviour following food calling could be a social reinforcement for broody hens.     

Effect of feed and water deprivation or force-feeding on plasma prolactin concentration in turkey hens

Plasma concentrations of prolactin (Prl), glucose, corticosterone, and D(-)-3-hydroxybutyrate (DBHB) were compared in nonlaying, nonincubating turkey hens subjected to feed and/or water deprivation. Neither Prl nor corticosterone concentrations were significantly (P greater than 0.05) altered by any of the treatments, whereas fasting significantly (P less than 0.05) reduced the concentration of glucose and increased the concentration of DBHB. Plasma levels of Prl in incubating hens were significantly (P less than 0.05) reduced by nest deprivation either in the absence of feed and water or when the hens were force-fed the normal intake for a laying hen. After 48 h of nest deprivation, the hens resumed nesting within 5 min of being returned to the pen although the plasma levels of Prl were low. Neither nest attentiveness nor the concentration of Prl were affected by force-feeding the hens while they were incubating eggs. The concentration of glucose increased in response to force-feeding or nest deprivation, whereas the concentration of corticosterone was increased only by force-feeding. These results suggest that Prl may not be involved in the striking changes in both intermediary and water metabolism which occur during incubation in the turkey hen. Furthermore, since incubation behavior can occur in the presence of low concentrations of Prl, elevated levels of Prl during broodiness appear to be maintained by a stimulus associated with the nest itself or some other aspect(s) of the environment.     

Increased proliferative activity and programmed cellular death in the turkey hen pituitary gland following interruption of incubation behavior

Incubation behavior or broodiness in turkey hens is characterized by ovarian regression, hyperprolactinemia, and persistent nesting. Nest-deprivation of incubating turkey hens results in disruption of broodiness accompanied by a precipitous decline in plasma prolactin (PRL) concentrations. The objective of the present study is to examine cellular changes in the pituitary gland associated with nest-deprivation for 0, 1, 2, 3, 4, or 7 days. Bromodeoxyuridine (BrdU) was administered prior to kill to study proliferative activity. Pituitary tissue sections were immunostained using turkey growth hormone (GH) antibody, and/or chicken PRL peptide antibody, and BrdU antibody. Plasma PRL concentrations declined significantly following nest-deprivation for 1 or more days. The midsagittal pituitary area immunoreactive (ir) to GH was significantly increased while that of PRL was significantly decreased following nest-deprivation for 2 or more days. Terminal deoxy-UTP nick end labeling and PRL-immunostaining revealed an abundance of apoptotic nuclei in both cephalic and caudal lobes of the anterior pituitary gland, suggestive of programmed cellular death of lactotrophs in the pituitary gland of hens nest-deprived for 2 or more days. Mammosomatotrophs were abundant in hens nest-deprived on Day 0 but were absent in hens nest-deprived for 1 or more days. Proliferating (BrdU-ir) cells were significantly abundant in the pituitary cephalic and caudal lobes following nest-deprivation for 1 or more days but were absent on Day 0 or in laying hens. Dual-labeling studies indicated that most of the BrdU-ir nuclei in the caudal lobe were not colocalized in somatotrophs in hens nest-deprived for 1-4 days but did colocalize with GH following 7 days of nest-deprivation. In conclusion, nest-deprivation of incubating turkey hens results in 1) a precipitous decline in plasma PRL concentration, 2) programmed cell death of lactotrophs, 3) disappearance of mammosomatotrophs, 4) increased proliferative activity of pituitary cells, and 5) recruitment of somatotrophs arising primarily from mitosis of nonsomatotrophic cells.     

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)     

鸟类的父本行为及其内分泌调控机制研究进展

飞翔能力帮助鸟类极大地扩展了生存空间,使其能够迅速移动来应对各种局部环境的变化。然而,个体发育早期,不具备这样的能力,使其极不适应环境,需要大量的亲本照顾。不同于哺乳类动物主要依赖母本行为,雄性鸟类表现出了大量的父本行为,诸如筑巢行为、孵卵行为和育雏行为等。针对这一系列行为及其调控机制,本文进行了归纳:1)筑巢行为常常伴随着雄性的求偶行为,睾酮对两种行为均有促进作用,加压素也促进筑巢行为。2)孵卵行为可以传递热量,保护和帮助子代发育;同时会刺激泌乳素释放,而泌乳素又会进一步促进孵卵行为;此时的睾酮水平下降。3)育雏行为与雏鸟的发育速度有关,晚成鸟需要更多的父本照顾;与孵卵行为的调控相似,泌乳素升高,睾酮降低;孕酮也参与调控父本行为。4)环境压力通过影响皮质酮和泌乳素水平的变化,调节鸟类的父本行为。综上,在鸟类父本行为形成和表现过程中,睾酮和泌乳素先后发挥着主要的调控作用,并且受到环境压力的影响。然而,在神经内分泌水平上,研究非常缺乏,需要加强。     

Gregarious nesting in relation to floor eggs in broiler breeders

Gregarious nesting has often been observed in laying hens, where hens prefer to visit a nest already occupied by other hens over empty nests. This may result in overcrowding of the nests which is considered a welfare issue and, moreover, can increase the economic issue of floor eggs. This study aimed to describe gregarious nesting and spatial behavior in broiler breeders and how this relates to genetic background, fearfulness and mating behavior. Five commercially available genetic lines of broiler breeders were housed in 21 pens of 550 females and 50 males (six pens for lines 1 and 2, five pens for line 3 and two pens for lines 4 and 5) during the ages 20–60 weeks. Every 10 weeks, the plumage condition and wounds were assessed of 50 random hens per pen. Avoidance distance and novel object tests were performed to assess fearfulness at four time points. Distribution of eggs over nests was observed for 6 weeks at the onset of egg production at 26 weeks of age, and use of space was recorded at four time points, while (floor) egg production was noted daily per pen. We found differences between genetic lines over time in plumage condition and prevalence of wounds. Fear of humans was highest at the earliest age tested and did not correlate with general fearfulness as assessed by the novel object test. The distribution of eggs over nests was related to genetic background and was more uneven at the earliest age compared to later ages, and a more uneven distribution was correlated with an increased percentage of floor eggs. Distribution of birds over the litter area differed between the genetic lines, and less use of the litter area was correlated with an increased fear of humans and presence of wounds, suggesting an association with aggressive mating behavior. This difference in distribution of the birds could also explain the correlation between increased presence of wounds and decreased percentage of floor eggs. It is concluded that broiler breeders do show gregarious nesting, which is affected by genetic background. Both increased gregarious nesting and wounds are related to increased floor egg percentage, which should be studied further in broiler breeder research. Genetic selection for even use of the available nests and of the litter and slatted area would therefore support both broiler breeder welfare and performance.