Academic literature on the topic 'Chicks'

Offspring ornamentation typically occurs in taxa with parental care, suggesting that selection arising from social interactions between parents and offspring may underlie signal evolution. American coot babies are among the most ornamented offspring found in nature, sporting vividly orange-red natal plumage, a bright red beak, and other red parts around the face and pate. Previous plumage manipulation experiments showed that ornamented plumage is favored by strong parental choice for chicks with more extreme ornamentation but left unresolved the question as to why parents show the preference. Here we explore natural patterns of variation in coot chick plumage color, both within and between families, to understand the context of parental preference and to determine whose fitness interests are served by the ornamentation. Conspecific brood parasitism is common in coots and brood parasitic chicks could manipulate hosts by tapping into parental choice for ornamented chicks. However, counter to expectation, parasitic chicks were duller (less red) than nonparasitic chicks. This pattern is explained by color variation within families: Chick coloration increases with position in the egg-laying order, but parasitic eggs are usually the first eggs a female lays. Maternal effects influence chick coloration, but coot females do not use this mechanism to benefit the chicks they lay as parasites. However, within families, chick coloration predicts whether chicks become “favorites” when parents begin control over food distribution, implicating a role for the chick ornamentation in the parental life-history strategy, perhaps as a reliable signal of a chick’s size or age.

AbstractAdult Nazca boobies (Sula granti) show an unusual interest in both conspecific and congeneric nestlings, visiting them at their nest sites and performing mixtures of affiliative, aggressive, and sexual behaviours. Using a 20 year database from a large Nazca booby colony on Isla Española, Galápagos Islands, Ecuador, we describe the behaviour and the individuals performing the behaviour. Non-parental Adult Visitors ('NAVs') are typically 'unemployed' (non-breeding birds or recently failed breeders), and make visits of 1-60 min to unguarded chicks. Males and females are equally likely to exhibit the behaviour, if they are unemployed; since most unemployed birds are male, due to a sex ratio bias, most NAVs are male. Very young chicks and chicks nearing fledging are not visited, because young chicks are always attended by protective parents, and old chicks can defend themselves. When acting affiliatively, NAVs may simply stand by the chick, or may preen it and present gifts of pebbles and feathers. Aggression by the NAV often leaves scratches on the chick's body, but seldom causes the chick's death directly. However, landbirds take blood-meals from the scratches during food shortages, deepening the wound and eventually killing the chick. The least common NAV behaviour is sexual, in which adults perform male copulatory behaviour with the chick. Sexual behaviour occurs in 14.3% of visits by males, and 6.8% of visits by females. NAV behaviour is the direct or indirect cause of mortality of up to 24.6% of chicks, representing up to 41.6% of all deaths, in a given year. Approximately 80% of non-breeding birds in a given year show NAV behaviour, and since most adults are non-breeders at some point in life, most adults show NAV behaviour at some point. We propose a number of hypotheses to explain the causation of this puzzling and ecologically important behaviour.

The sex detection of chicks is an important work in poultry breeding. Separating chicks of different sexes early can effectively improve production efficiency and commercial benefits. In this paper, based on the difference in calls among one-day-old chicks of different sexes, a sex detection method based on chick calls is designed. Deep learning methods were used to classify the calls of chicks and detect their sex. This experiment studies three different varieties of chicks. The short-time zero-crossing rate was used to automatically detect the endpoints of chick calls in audio. Three kinds of audio features were compared: Spectrogram, Cepstrogram and MFCC+Logfbank. The features were used as the input in neural networks, and there were five kinds of neural networks: CNN, GRU, CRNN, TwoStream and ResNet-50. After the cross-comparison experiment of different varieties of chicks, audio features and neural networks, the ResNet-50 neural network trained with the MFCC+Logfbank audio features of three yellow chick calls had the highest test accuracy of 83% when testing Three-yellow chicks’ calls. The GRU neural network trained with the Spectrogram audio features of native chick calls had the highest test accuracy of 76.8% when testing Native chicks’ calls. The ResNet-50 neural network trained with Spectrogram audio features of flaxen-yellow chick calls had the highest test accuracy of 66.56%when testing flaxen-yellow chick calls. Multiple calls of each chick were detected, and the majority voting method was used to detect the sex of the chicks. The ResNet-50 neural network trained with the Spectrogram of three yellow chick calls had the highest sex detection accuracy of 95% when detecting the three yellow chicks’ sex. The GRU neural network trained with the Spectrogram and cepstrogram of native chick calls and the CRNN network trained with the Spectrogram of native chick calls had the highest sex detection accuracy of 90% when detecting the native chicks’ sex. The Twostream neural network trained with MFCC+Logfbank of flaxen-yellow chick calls and the ResNet-50 network trained with the Spectrogram of flaxen-yellow chick calls had the highest sex detection accuracy of 80% when detecting the flaxen-yellow chicks’ sex. The results of the cross-comparison experiment show that there is a large diversity between the sex differences in chick calls of different breeds. The method is more applicable to chick sex detection in three yellow chicks and less so in native chicks and flaxen-yellow chicks. Additionally, when detecting the sex of chicks of a similar breed to the training chicks, the method obtained better results, while detecting the sex of chicks of other breeds, the detection accuracy was significantly reduced. This paper provides further perspectives on the sex detection method of chicks based on their calls and help and guidance for future research.

The adaptive significance of asynchronous hatching in the Herring Gull, Larus argentatus, was examined during the summer of 1984 at Kent Island, New Brunswick. Chick growth and behaviour in 28 experimental three-egg clutches in which the eggs hatched synchronously (i.e., hatch interval ≤ 24 h between the first (A chick) and last (C chick) hatched) were compared with that of 15 control three-egg nests with normal hatching asynchrony (A–C hatch interval > 24 h). All chicks had similar hatch weights, except for control C chicks, which on average were significantly lighter than their nest mates and experimental chicks. Growth rates were also similar for all chicks within and between groups, except for control C chicks, which grew at a significantly slower rate compared with nest mates and experimental chicks. In control broods, C chicks disappeared first significantly more often than A or B chicks. In experimental broods, a similar proportion of A, B, and C chicks disappeared first. Survivorship, through to day 5 posthatch, was significantly lower for control C chicks than for control A and B chicks as well as experimental chicks. These results suggest that the benefit Herring Gulls achieve hatching their eggs asynchronously results from the competitive advantage accrued to the A chick (and the B chick to some degree), which allows them to obtain more food, especially during periods of food stress. Subsequently the probability of survival of the older, more fit chick(s) is enhanced.

What mechanisms underlie learning in newborn brains? Recently, researchers reported that newborn chicks use unsupervised statistical learning to encode the transitional probabilities (TPs) of shapes in a sequence, suggesting that TP-based statistical learning can be present in newborn brains. Using a preregistered design, we attempted to reproduce this finding with an automated method that eliminated experimenter bias and allowed more than 250 times more data to be collected per chick. With precise measurements of each chick’s behavior, we were able to perform individual-level analyses and substantially reduce measurement error for the group-level analyses. We found no evidence that newborn chicks encode the TPs between sequentially presented shapes. None of the chicks showed evidence for this ability. Conversely, we obtained strong evidence that newborn chicks encode the shapes of individual objects, showing that this automated method can produce robust results. These findings challenge the claim that TP-based statistical learning is present in newborn brains.

AbstractExperiments are reported on filial imprinting and leadership among white leghorn chicks in relation to family integration. Chicks hatched in isolation were given their first exposure to certain parental stimuli (a moving person or clucking sounds recorded from a broody hen) at various ages after hatching from the first to 10th day. Logistic regression and multiple likelihood analysis of the results showed that a significant tendency to follow or to be attracted to parental stimuli was much the greatest during the first day after hatching and then declined exponentially during the rest of the first week. There was a significant correlation between visual and auditory responses to parental stimuli, as well as between a chick's positive responses to clucking and the giving of distress cries by the chick when clucking ceased. Some individual chicks showed a significant tendency to lead the other chicks of a group to stimuli representing the mother, such as a source of warmth, or to the maternal voice (recorded clucking from a speaker).

In 1987 and 1988, common tern (Sterna hirundo) chicks at a colony near Port Colborne, Ontario, were individually colour banded according to known hatch order. Intraclutch hatch intervals produced size disparities among chicks at brood completion; third-hatched chicks were significantly lighter and at a significant survival disadvantage compared with their earlier-hatched siblings. There were differences in feeding rates according to hatch order and many third-hatched chicks obtained fewer or no feedings during our periods of observation. Sixty-five chicks known to have abandoned their home broods gained acceptance into foreign broods. Chicks that remained in the foreign brood for more than 2 days (average residency 11.9 ± 5.3 days; n = 26) were fed and brooded by the foster parents, were on average older than the youngest resident chick, but were not always the last hatched in their home brood. Conversely, chicks that were in a foreign brood for less than 2 days were no different in age from the youngest resident chick. Survival and fledging success was highest for chicks accepted into two chick broods in which they were older than the resident second chick; in effect, the adoptee became the second chick. Parents that accepted a foreign chick for more than 2 days experienced a seasonal fitness loss compared with nonadopting parents. As the only viable option available to them, selection favours movement away from home broods by chicks that may be disadvantaged there.

Abstract. This study was made to compare physical chick quality indicators such as chick length and feather colour and their effects on the uniformity and subsequent growth performance in broiler. For this reason; 600 day old male chicks were used. Chicks were classified into two groups on the basis of their feather colour: deep and light yellow. Then, chicks in each group were further divided into three groups as small, middle and large according to their body length. The length of the middle group animals was varied between 18.0–18.3 cm, while that of the largest group was greater than 18.3 cm and the small group was lesser than 18.0 cm. A positive correlation between chick length and chick weight was observed in all groups at the 0 day of age. Body length uniformity in day old chick was more important than body weight uniformity. Longer chicks exhibited better growth potential throughout the experiment. The feeding efficiency and survival rate of longer chicks were numerically greater compared to smaller chicks. There were no significant differences for subsequent growth parameters in feather colour groups. Consequently; length of day old chick can be used as important criteria for selection of higher quality chicks having better growth performance.

To test whether Dovekies, Alle alle (small arctic alcids laying single-egg clutches), can increase parental effort, we increased food demand in their nests in two experiments. First, we introduced a second chick to the nests. Second, we rotated a number of chicks among a smaller number of nests, producing equivalents of 2, 1.5, and 1 (control) chicks per nest. Fledging success in the nests with twins (0.63 chick per nest) was higher than in unmanipulated broods of 1 chick (0.46 chick per nest). Chicks that fledged successfully in the two experiments grew at significantly lower rates and fledged at lower body masses and later than did rotated control chicks and unmanipulated single chicks. The latter two groups did not differ one from another. Growth rates and body masses of the chicks from the 2/1 rotation group (equivalent to 2 chicks per nest) were too low to indicate any substantial increase in the rate of provisioning by adults (over the rate satisfying the maximum energy consumption of an unmanipulated single chick). We associate this with the adults' energetically expensive mode of foraging and high field metabolic rates. However, the deferred fledging of rotated and twinned chicks might have considerably increased the total food demand in their nests (from hatching to fledging) that had to be met by the parents.

AbstractCommercially reared ostrich chicks are typically kept in barren, indoor environments. This experiment investigated the effects of environmental enrichment on the pecking behaviour, exploration, food consumption and novelty responses of ostrich chicks aged 10 to 21 days. Four groups of 20 randomly selected ostrich chicks were housed in heated huts at one day of age (Day 1), and at Day 10 were allowed access to sand-covered areas (30 m2) that were either barren (control: n = 2 groups) or enriched with cabbage, coniferous cones and sticks (enriched: n = 2 groups). Pecking behaviour was recorded by focal sampling the behaviour of five chicks per group for four 5 min periods per day on Day 10 and Day 13. All enriched chicks pecked at the cabbage, of which they consumed considerable amounts (26 ± 3 g/chick/day). The enriched chicks did not have higher overall pecking frequencies but tended to peck less at fixtures in the pen, compared to control chicks. Additionally, the enriched chicks showed increased exploration in terms of the percentage of chicks observed outside the heated huts. In a novel object test, enriched chicks stayed closer to and delivered more pecks at sorrel (Rumex acetosa) than did control chicks, whereas there was no difference between the treatment groups in their response to adult ostrich feathers. Enriched chicks consumed more food (79 ± 0.4 g/chick/day) than did control chicks (67 ± 09 g/chick/day) during the experimental period. We suggest that environmental enrichment improves the welfare of ostrich chicks in terms of increasing exploration and reducing pecking at fixtures in the pen, without compromising food consumption.