Aufzucht von Chilemeerespelikane (Pelecanus occidentalis thagus) im Vogelpark Walsrode mit Vergleichen zu anderen publizierten Erfahrungen mit Pelikanen

The probable world first captive breeding success in Chilean Brown Pelican (Pelecanus occidentalis thagus) in captivity is reported. Two chicks were hand reared at Walsrode Birdpark, Germany in 2006. Parents were imported in October 2005 and were wild birds that had been injured and subsequently rescued. All 10 adult birds demonstrated detrimental and chronically handicaps. First eggs were laid in January 2006. Eggs were incubated artificially at 37.1 °C and 56% rel. humididty. Two chicks hatched after 33 days of incubation. First feeding was made one day after hatching in the morning. Food was given 5 times a day. Until the 8th day after hatching, exclusively cut naked baby rats were fed. For stimulating the digestion and providing a good intestinal flora Lactobacillus powder was used and food was warmed up before application. After 8 days the diet was changed to fish. For development see figures. Worth to mention is the black-purple colour of the freshly hatched chicks which became successively paler with age. Also the development of the feather areas is characteristic for this (sub)-species. Taxonomy is discussed with some morphological arguments that are typical for subspecies. Nevertheless, some indications of possible breeding barriers between subspecies could support the suggestions for species status. Hatching and rearing data are compared with dates from other zoos and species of pelicans. The good development of the Walsrode birds based on the data and methods described leaves this article useful as a reference guideline for hand rearing pelicans.     

Adaptive difference in daily timing of hatch in two locust species,Schistocerca gregaria and Locusta migratoria: The effects of thermocycles and phase polyphenism

This study examined the effects of temperature and phase polyphenism on egg hatching time in the desert locust, Schistocerca gregaria, and the migratory locust, Locusta migratoria. The two species exhibited differences and similarities in hatching behavior when exposed to different temperature conditions. In 12-h thermocycles of various temperatures, the S. gregaria eggs hatched during the cryoperiod (low temperature period), whereas L. migratoria eggs hatched during the thermoperiod (high temperature period). The eggs of both species hatched during the species-specific period of the thermoperiod in response to a temperature difference as small as 1 °C. Furthermore, the locusts adjusted hatching time to a new thermal environment that occurred shortly before the expected hatching time. In both species, the hatching of the eggs was synchronized to a specific time of the day, and two hatching peaks separated by approximately 1 day were observed at a constant temperature after the eggs were transferred from thermocycles 3 days before hatching. Eggs laid by gregarious females hatched earlier than those laid by solitarious females in S. gregaria but this difference was not observed in L. migratoria.     

Beobachtungen zur Fortpflanzungsbiologie des Stirnbandibis,Harpiprion caerulescens

Summary In the Pantanal of Mato Grosso hatching and rearing of the chicks of the Plumbeous Ibis (Harpiprion caerulescens) was observed towards the end of the dry season (mid-August until mid-October). Mating and nest-building was already noticed earlier in the year (March/April). A nest was found 12 m up in a tree in a sparsely wooded area. It was built of dry twigs and its cavity was lined with leaves and grass. Both partners shared in nest-building. The clutch consisted of two pale grey eggs (67 × 44 mm). The chicks hatched on 6th September. Until they were ten days old, the two young birds received constant attention from both parents who took over from each other five times a day and both fed the young. Later, the young birds were gradually left unprotected for longer periods. They fledged on the 43rd day after hatching.     

Hatching order affects offspring growth,survival and adult dominance in the joint‐laying Pukeko Porphyrio melanotus melanotus

In birds with asynchronous hatching, hatching order is an important factor in determining offspring phenotype. Many previous studies have demonstrated that later‐hatched offspring show reduced growth and survival during development. However, few studies have followed individuals from hatching to adulthood to test whether the effects of hatching order persist into later life. Here, we explore patterns of hatching order and fitness‐related traits in the Pukeko Porphyrio melanotus melanotus, a cooperatively breeding bird that lives in stable social groups that form linear dominance hierarchies. Pukeko groups sometimes contain two breeding females that lay eggs in the same nest (joint‐laying). Thus, competition between nest‐mates can influence the relative fitness of each laying female. We show that in both single‐clutch and joint‐clutch nests, earlier‐hatched Pukeko chicks grow faster and survive better than later‐hatched brood‐mates. Moreover, earlier‐hatched chicks achieve higher dominance ranks as adults, making this study one of the first to find a relationship between hatching order and adult dominance in wild birds. Finally, we show that in groups with two breeding females, the chicks of the primary female hatch earlier than the chicks of the secondary female. As a result, the offspring of the primary female may be at a competitive advantage, which could have important implications for social dynamics in this species.     

Adaptive hatching hypotheses do not explain asynchronous hatching in Brown-headed Parrots Poicephalus cryptoxanthus

At the core of the suite of adaptive hatching hypotheses advanced to explain asynchronous hatching in birds is the assumption that if food is not limited then all the hatchlings will develop normally to adulthood. In this study Brown-headed Parrot Poicephalus cryptoxanthus chicks were hand fed and weighed on a daily basis. Their respective masses were compared using a reparamatised Richards growth model. The results show that although the second and third hatched chicks initially grow faster than the first, the final mass attained by the third chick is significantly less than either of its siblings. Adaptive hatching hypotheses do not explain this result. We propose that the third chick is opportunistic and that is has evolved as insurance against prior chicks surviving because of interspecific pressure on the breeding biology of the species.     

Effects of removal of chicks from hens on concentrations of prolactin, luteinizing hormone and oestradiol in plasma of brooding Gifujidori hens.

Gifujidori hens were allowed to repeat a breeding cycle in one season. In the first breeding cycle the duration of the brooding (raising chicks) stage was limited to 3 weeks, whereas in the second breeding cycle it was limited to 1 week by removing all chicks from mother hens. In the first breeding cycle, plasma prolactin (PRL) was high during the incubation period, but rapidly decreased on the day of hatching and reached minimum values about 1 week after hatching. In contrast, plasma luteinizing hormone (LH) concentrations were low during the incubation period, but after hatching they gradually increased and reached peak values immediately after removal of chicks. Concentrations of oestradiol in plasma were low in the incubation and brooding stages but increased significantly immediately after removal of chicks. In the second breeding cycle, changes in PRL and LH concentrations were similar to those observed in the first breeding cycle except that even greater increases in plasma LH and oestradiol concentrations were observed one week after hatching when the chicks were removed. These results suggest that coexistence of newly hatched chicks may suppress LH secretion from the pituitary of the hen in the natural breeding cycle.     

Effect of cyclical cold stress during embryonic development on aspects of physiological responses and HSP70 gene expression of chicks

The objective of the present study was to evaluate the effects of cyclical lower incubation temperature at different embryonic ages on the hatchability, body and organs weights, thyroid hormones, and liver HSP70 gene expression of newly hatched chicks. In a completely randomized design, fertile eggs of a broiler breeder (34 weeks of age) were assigned to three treatment groups with six replicates and 145 eggs per each. The treatment groups were as: control group (C) that eggs were incubated at 37.6 °C during the whole incubation period; incubation temperature was decreased to 36 °C for 3 h per day at embryonic age from 12 to 14 (T1); and incubation temperature was decreased to 36 °C for 3 h per day at embryonic age from 15 to 17 (T2). No significant difference was found among treatments for hatchability (P>0.05). There were no differences (P>0.05) among treatments for body weight and liver weight, while heart weight of chicks in T1 and T2 groups were significantly higher than the control group (P<0.05). There were no differences (P>0.05) among treatments for the levels of thyroid hormones, however, the levels of both hormones tended to increase in chicks exposed to cold stress (T1 and T2). Chicks in T2 group had higher liver HSP70 gene expression compared with those in T1 and the control group (P<0.05). Cold stress in both incubation periods had no significant effect on the plasma levels of aspartate aminotransferase and alanine aminotransferase. Treatments had no effect on the plasma levels of glucose, cholesterol and triglyceride. The results of this study suggest that cyclical lower incubation temperatures (36 °C) at the embryonic age from day 15–17 could induce the liver HSP70 gene expression, without negative effects on the hatchability and body weight of hatched chicks.     

朱鹮迁地保护研究

朱鹮（Nipponia mppon）是当今世界最濒危的鸟类之一,现存总数不过 40余只。由于生存环境的改变和种群生命力的脆弱,朱鹮数量急剧下降。中国自1986年开始人工繁殖朱鹮,1992年人工孵化并育活3只幼鸟,这是人工繁殖朱鹮成功的首次记录。这篇文章总结了朱鹮的野外生态,实验室研究及人工饲养、繁殖。     

Captive breeding for reintroduction: influence of management practices and biological factors on survival of captive kaki (black stilt)

An important component of the restoration strategy for the critically endangered kaki or black stilt (Himantopus novaezelandiae) is captive breeding for release. Since 1981 1,879 eggs were collected from wild and captive pairs, with birds laying up to four clutches. Eggs were incubated artificially and most chicks reared by hand until released as juveniles (about 60 days) or sub‐adults (9–10 months). Because survival in captivity is a significant determinant of the number of birds available for release, we wished to identify sources of variation in mortality to assess potential impacts of management on productivity. Hatchability was 78% for captive‐laid eggs and 91% for wild‐laid eggs. Survival of hatched eggs was 82% by 10 months of age for both wild and captive birds. Most egg mortality occurred early in incubation and around hatching: the timing of mortality was unaffected by whether birds were captive or wild, hybrid or pure kaki, or when eggs were laid. Heavier hatchlings showed higher initial survival, as did chicks from wild parents. Hatchlings from fourth‐laid eggs showed lowest survival, even though hatchling mass tended to increase with hatch order. Survival of chicks subjected to major health interventions was 69% after 4 months. No differences in survival were found between different genders, hybrids and pure kaki, hand‐reared or parent‐reared birds, chicks hatching early or late in the season, different seasons, different‐sized groups of chicks, chicks reared in different brooders, juveniles kept in different aviaries, and chicks from subsequent clutches. Birds subjected to minor health interventions were equally likely to survive as healthy chicks (82%). Survival was high despite aggressive management (quadruple clutching and collecting late in the season). Differences between captive and wild birds suggest further improvements could be made to captive diet. Wide variation in hatchability between parent pairs substantiates the practice of breaking up poorly performing pairs. Zoo Biol 0:1–16, 2005. © 2005 Wiley‐Liss, Inc.     

Effect of hatching system and prophylactic antibiotic use on serum levels of intestinal health biomarker diamine oxidase in broilers at an early age

To overcome some of the disadvantages of conventional hatcheries, a new concept is being explored in the broiler industry: on-farm hatching. In on-farm hatching systems, broiler eggs are transported to the broiler house on day 18 of incubation. On-farm hatched chicks hatch in a low dust environment, are immediately exposed to light, and have instant access to nutrients and water. Previous studies reported that on-farm hatching systems provide birds with an improved intestinal health and a lower feed conversion rate; resulting in a reduced use of antibiotics. Although it is generally agreed that the intestinal health of on-farm hatched chicks is better, the causative factors remain largely unknown. To explore the effect of hatching system on intestinal development, a full factorial in vivo experiment was designed, taking into account commercial age (minus two days, D-1, D1 and D2) and hatching condition (hatchery-born, hatchery-born with Spectoliphen 100 (SL) treatment, and on-farm hatched using the NestBorn-system) as factors. To assess intestinal development, diamine oxidase (DAO) serum levels were measured. DAO, a highly active intracellular enzyme that is synthesised mainly by the intestinal mucosal cells, is generally used as an indicator for intestinal maturation and intestinal permeability (IP) in mammals and birds. Analysis of serum samples showed that serum DAO levels in hatchery-born chicks were significantly lower compared to their on-farm hatched counterparts on all four days, suggesting that the intestinal development in the latter took place earlier. However, the long-term effect was not explored in this study. An additional comparison between the hatching systems was made, not according to commercial age, but in reference to time of access to feed. In this comparison, no differences between the two groups were observed. Interestingly, in the hatchery-born chicks, no compensatory development of the intestines took place within the time span of this experiment. The effect of SL during the first days on intestinal development and IP of chicks remains poorly understood and requires further investigation.     

Body mass changes in Brünnich's guillemots Uria lomvia with age and breeding stage

Body mass of Brünnich's guillemots Uria lomvia breeding at Coats Island, Canada, was measured during incubation and chick‐rearing in 1988–2001. In most years, mass increased during incubation and fell after hatching, leveling off by the time chicks were 18 d old, close to the age at which chicks departed. Mass during incubation increased with age up to about 12 yr, but the mass of birds brooding chicks was not related to age. The trend towards increasing mass during incubation was mainly a consequence of mass increases of young breeders as older birds maintained a constant mass. The variation in adult mass with age during incubation seems likely to reflect age‐related variation in foraging ability, but the loss of mass after hatching, being greater for older birds, appears best explained as a response to the demands of provisioning chicks, with older birds transferring their accumulated reserves to their chicks via higher provisioning rates.     

Increased lifetime reproductive success of first‐hatched siblings in Common Kestrels Falco tinnunculus

Order of birth has profound consequences on offspring across taxa during development and can have effects on individuals later in life. In birds, differential maternal allocation and investment in their progeny lead to variance in the environmental conditions that offspring experience during growth within the brood. In particular, laying and hatching order have been proposed to influence individual quality during the growing period, but little is known about the fitness consequences that these two factors have for offspring from a lifetime perspective. We explored the effect of laying and hatching order on post‐fledgling survival (measured as recruitment probability) and lifetime reproductive success (LRS) in Common Kestrels Falco tinnunculus, using a long‐term and individual‐based dataset. First‐hatched chicks showed higher survival probability and LRS than their siblings. This effect was not due to body condition of the individuals at adulthood, the quality of their mates or the reproductive outcome compared with later‐hatched individuals. Instead, first‐hatched chicks had a higher recruitment probability. This could be explained by the higher body condition attained by first‐hatched chicks at the end of the nesting period, perhaps due to an enhanced competitive advantage for food over their siblings at the time of hatching. Laying order, in contrast to hatching order, appeared to have little or no effect on LRS. Our results suggest that hatching order within siblings predicts fitness, and that better early‐life conditions during growth experienced by first‐hatched chicks improve first survival and then recruitment, resulting in an enhanced LRS.     

Observations on the breeding biology and behaviour of the Lesser Jacana,Microparra capensis

Two Lesser Jacana nests were found in Hwange National Park, Zimbabwe and were observed over a period of four months beginning in March 2000. Both sexes were involved in preparing the breeding platform, incubation, and caring for the chicks, which were not carried by the adults. Both nests had three eggs. The incubation period for one clutch of eggs was not less than 19 days. The chicks all hatched on the same day and remained in the vicinity ofthe nest for the first few days where they were brooded by an adult. Initially the adults brought food to the chicks but the chicks started feeding themselves when they moved away from the nest. Ten days after hatching the chicks had doubled in size and were walking confidently with the attending adult some distance from the nest. First flight was seen at 32 days old, and the chicks appeared to be independent 63 days after hatching.     

Development of restoration techniques for Hawaiian thrushes: Collection of wild eggs,artificial incubation,hand‐rearing,captive‐breeding,and re‐introduction to the wild

From 1995 to 1999, two species of endemic Hawaiian thrushes, `Oma`o (Myadestes obscurus) and Puaiohi (M. palmeri), were captive‐reared and re‐introduced into their historic range in Hawai`i by The Peregrine Fund, in collaboration with the U.S. Geological Survey–Biological Resources Division (BRD) and the Hawai`i State Department of Land and Natural Resources. This paper describes the management techniques that were developed (collection of wild eggs, artificial incubation, hand‐rearing, captive propagation, and release) with the non‐endangered surrogate species, the `Oma`o; techniques that are now being used for recovery of the endangered Puaiohi. In 1995 and 1996, 29 viable `Oma`o eggs were collected from the wild. Of 27 chicks hatched, 25 were hand‐reared and released into Pu`u Wa`awa`a Wildlife Reserve. Using the techniques developed for the `Oma`o, a captive propagation and release program was initiated in 1996 to aid the recovery of the endangered Puaiohi. Fifteen viable Puaiohi eggs were collected from the wild (1996–1997) to establish a captive breeding flock to produce birds for re‐introduction. These Puaiohi reproduced for the first time in captivity in 1998 (total Puaiohi chicks reared in captivity 1996–1998 = 41). In 1999, 14 captive‐bred Puaiohi were re‐introduced into the Alaka`i Swamp, Kaua`i. These captive‐bred birds reproduced and fledged seven chicks in the wild after release. This is the first endangered passerine recovery program using this broad spectrum of management techniques (collection of wild eggs, artificial incubation, hand‐rearing, captive‐breeding, and release) in which re‐introduced birds survived and bred in the wild. Long‐term population monitoring will be published separately [BRD, in preparation]. Zoo Biol 19:263–277, 2000. © 2000 Wiley‐Liss, Inc.     

Sibling Growth Patterns in Great tits: Does Increased Selection on Last-hatched Chicks Favour an Asynchronous Hatching Strategy?

In birds, competitive abilities of siblings in relation to their sex and the magnitude of hatching delay are still poorly understood. We compared the sex-specific growth of the last-hatched, competitively disadvantaged chicks with that of synchronously hatched chicks in two successive years. Sons exhibited higher growth rates than daughters in a year with delayed onset of breeding, and this sex-related difference was more pronounced among the asynchronously hatched chicks. Females apparently do not selectively allocate more resources to the last-laid eggs because neonatal body mass and the growth rate of asynchronously hatched chicks did not differ between years, despite the fact that in one of the years, asynchronous chicks hatched from replaced eggs taken randomly from other nests and not from eggs laid last by the incubating female. Among chicks that survived, moderately asynchronous siblings grew at a lower rate than synchronous ones, whereas no difference in mass gain was revealed between synchronous and strongly asynchronous siblings irrespective of their contrasting competitive abilities. We suggest that selection of the fittest asynchronous chicks may improve the overall quality of asynchronous broods, thus favouring the maintenance of asynchronous hatching strategies in variable environments.     

Sex of the first hatched chick influences survival of the brood in the herring gull (Larus argentatus)

Differences in the growth rate of male and female offspring can result in different parental rearing costs for sons and daughters. Such differences may also influence the survival chances of male and female offspring when conditions are unfavourable. In birds, hatching asynchrony leads to hierarchical competition for food between siblings. Therefore, the sex of the chick in the first hatched position in the brood may influence breeding success by affecting the extent to which the later hatched chicks can compete for resources. The interaction between brood sex composition and chick performance in the herring gull Larus argentatus was examined under different environmental conditions. When environmental conditions were relatively good, chick survival within broods was better when a female was first to hatch, an effect that was most obvious later in the season. When conditions were poorer however, sex of the first hatched chicks was not related to brood survival. In neither situation did the overall primary sex ratio differ from equality. However in the year of relatively good food availability, the first chick in the brood was more likely to be male early in the season, which was when the disadvantageous effects on brood survival of males being in this position are weakest.     

Seasonal declines in reproductive success of the common tern Sterna hirundo: timing or parental quality?

Reproductive success declines over the course of the breeding season in many bird species. Two categories of hypothesis have been evoked to explain this decline. The “timing” hypothesis suggests that seasonal declines in breeding success are attributable to the date of laying. The “parental quality” hypothesis suggests that seasonal declines result from the fact that young, inexperienced, or low quality birds breed later in the season. To evaluate the relative importance of timing and parental quality, egg exchanges and removals were used to manipulate hatching dates of common terns Sterna hirundo. Indices of quality, attendance, provisioning rates, and reproductive success of birds in three experimental groups (delayed hatch pairs, advanced hatch pairs, and pairs induced to relay) were compared to those of date‐matched controls. Pairs that hatched chicks early raised more chicks than pairs hatching chicks late in the season, regardless of initial laying date. This suggests that hatching chicks early is advantageous in itself. Our results, however, also support the parental quality hypothesis. There was a significant negative relationship between natural laying date and fledging success, independent of hatching date. Differences in chick growth and survival suggest that higher quality adults may be able to compensate for the disadvantages of late hatching dates and achieve similar reproductive success to that of pairs hatching chicks early. We found that pairs hatching chicks late in the season were subject to more incidents of kleptoparasitism than those hatching chicks early. This may be a proximate factor contributing to seasonal declines in reproductive success for common terns, although such a mechanism would not be likely in non‐colonial species. Failure to control for egg quality may have biased the results of some prior egg exchange experiments. Additionally, altered cost of incubation may be an unavoidable confounding factor in studies designed to manipulate timing of breeding.     

Hand-rearing,growth, and development of the red bird of paradise (Paradisaea rubra) at the New York Zoological Park

Growth and development of six hand-reared red bird of paradise chicks was documented at the New York Zoological Park from March 1988 to May 1989. A total of 16 eggs were laid, of which 10 were fertile. Clutches consisted of two eggs and the female left the next infrequently during incubation. Two chicks left in the nest were apparently victims of parental abuse. Eggs were subsequently removed from the nest after 10–14 days, candled, and if fertile, were artificially incubated. The average incubation period was 16.6 days. Newly hatched chicks were without down and their eyes remained closed until approximately 6 days of age. Hand-reared chicks were maintained in Air Shield Infant Isolettes. The weight of newly hatched chicks was about 8 g, and the weight typically doubled during the first week. Ratios of food intake to body weight were highest between day 4 and 10. Pin feathers were visible on the wings after 4 days, and after 3 weeks, the chicks were fully feathered. Analysis of the diet revealed acceptable levels of iron, but vitamin A and E levels were higher than recommended for poultry chicks. This paper documents the first successful hand-rearing of any species of birds of paradise from hatching to fledging.     

Seasonal variation in reproductive measures of tropical Roseate Terns Sterna dougallih previously undescribed breeding patterns in a seabird

Seasonal variation in egg-laying, egg size, hatching success, hatchling mass, fledging success and chick growth of Roseate Terms Sterna dougallii breeding on Aride Island (Seychelles), Indian Ocean, were studied in 1997 and 1998. I investigated to what extent two patterns, common in a range of species, were followed by tropical Roseate Terns: (a) seasonal decrease in clutch size, egg size and breeding success and (b) an increase in breeding success with increasing egg weight. In 1997 (a poor year), the earliest nesting birds laid significantly smaller eggs, and chicks were lighter at hatching than those of peak nesting birds. The mean clutch size, of 1.04 eggs, showed no seasonal variation and no 'b'-eggs hatched. In 1998 (a good year) the earliest nesting birds laid eggs of similar size and their chicks were of similar weight to those of peak nesting birds. Mean clutch size, of 1.25 eggs, increased significantly through the season and about 60% of the 'b'-eggs hatched. In 1997, hatching success was 57% whereas in 1998 it was 80%. In both years, breeding success declined significantly through the season. The fact that the earliest breeding birds laid smaller eggs in a poor year and smaller clutches in a good year is in marked contrast to a range of other species, and to temperate-nesting Roseate Terns. Egg volume explained about half of the variance in hatchling mass in both years, but only 15% of the variation in linear growth rate. Hatching date was the only variable with a significant effect on fledging success. Roseate Terns on Aride seemed to sacrifice egg size and clutch size for earliness of laying. Presumably it is a strategy of older birds to lay as early as possible and may be regarded as a response of tropical Roseate Terns to breeding under relatively poor, and seasonally declining, food conditions.     

Effect of hatching time on time to first feed intake,organ development,enzymatic activity and growth in broiler chicks hatched on-farm

The conventional commercial hatcheries used today do not allow the newly hatched chicks to consume feed or water. Combined with natural variation in hatching time, this can lead to early hatched chicks being feed-deprived for up to 72 h before being unloaded at the rearing site. This study investigated the effects of hatching time on time to first feed intake and development of organs, digestive enzymes and productivity in terms of growth and feed conversion ratio in chicks hatched on-farm. Chicks were divided into three hatching groups (early, mid-term and late), and assessed over a full production cycle of 34 days. The results revealed that chicks remain inactive for a considerable amount of time before engaging in eating-related activities. Eating activity of 5% (i.e. when 5% of birds in each hatching group were eating or standing close to the feeder) was recorded at an average biological age (BA) of 25.4 h and a proportion of 50% birds with full crop was reached at an average BA of 30.6 h. Considering that the hatching window was 35 h in this study, the average chick probably did not benefit from access to feed and water immediately post-hatch in this case. At hatch, mid-term hatchlings had a heavier small intestine (30.1 g/kg bw) than both early (26.4 g/kg bw) and late (26.0 g/kg bw) hatchlings. Relative length of the small intestine was shorter in late hatchlings (735 cm/kg bw) than in mid-term (849 cm/kg bw) and early (831 cm/kg bw) hatchlings. However, the relative weight of the bursa fabricii was greater in mid-term (1.30 g/kg bw) than in early hatchlings (1.01 g/kg bw). At hatch, late hatchlings were heavier than early and mid-term hatchlings (P < 0.05), but by 3 days of age early hatchlings were heavier than mid-term and late hatchlings (P < 0.01). The only effect persisting throughout the study was a difference in the relative weight of the small intestine, where late hatchlings had heavier intestines than early hatchlings (P < 0.05). Thus, while there were differences between hatching groups, this study showed that the hatchlings seemed capable of compensating for these as they grew.