The aim of the study was to determine whether birds of different breeds, with different preferences for environmental elements and kept in identical conditions, would exhibit different behaviour and stress levels. The research material consisted of 50 laying hens of the Green-legged partridge (Zk), Polbar (Pb), and Leghorn (Lg) breeds. The birds were provided with identical environmental conditions. They were kept on litter in separate boxes, with 25 individuals of one breed per box, in the same building. An open field test was used in determining the behaviour of the birds. Levels of cortisol in serum and corticosterone in feathers were evaluated, and haematological and biochemical analyses of blood were performed. Leghorns proved to be a highly excitable and active breed whose needs cannot be fully satisfied in the standard conditions of large farms. Based on a differential leukocyte count, their hyperactivity was associated with increased stress. The Green-legged partridge exhibited the lowest stress levels. Birds kept in the same environmental conditions were found to differ significantly in the level of stress, probably because of differences in their behavioural needs and the possibilities of satisfying them. To reduce stress levels and improve the welfare of hens, it is necessary to verify their preferences first. Stress indicators are elevated in highly excitable birds, and the conditions on large farms are not conducive to meeting their behavioural needs.

ABSTRACT The aim of the study was to evaluate the emotional reactivity of hens with the use of physical parameters such as movement velocity and position of the selected parts of the body analysed by computer software - Tracker®. 200 Rhode Island White hens kept individually in a laying hen breeding farm were used in the study. The analysis of hens behaviour was performed with the use of Novel Object Test. Afterwards the video clips were analysed to determine behavioural reactivity with the use of Tracker® software by analysis of two control points: the upper part of the head and the peak of the tail. The results suggest that it is possible to use Tracker® software for evaluation of hens behavioural profile and this sort of analysis enables to classify hens to the groups of timid or curious/courageous birds based on the parameters of movement velocity of the upper part of the head and the peak of the tail and on the basis of the ratio between the position of the head and the tail.

ABSTRACT The aim of the study was to determine the impact of caponisation of Polbar (Pb) and Greenleg Partridge (Zk) breeds on the production performance, carcass composition, and the nutrient content and fatty acid profile in the breast and thigh muscles and abdominal fat. From 18 weeks of age to the end of the experiment, the Zk capons were significantly heavier than the cocks. The Zk capons had higher (p≤0.05) weight and share of breast and leg muscles. At 24 weeks of age, we noted an increase in the total content of n-3 PUFA and linolenic acid C18:3 in the breast muscles of the Zk and Pb capons. The content of PUFA and n-3 PUFA in thigh muscles and the n6/n3 ratio were reduced in the Pb capons at 24 weeks of age, compared with the Zk cocks. Caponisation of the Pb cocks had a beneficial effect on the final body weight, feed intake, and slaughter characteristics, in comparison with the non-caponised birds of this breed. A tendency towards an increased total share of PUFA and MUFA, a significantly higher content of n-3 PUFA, and a lower (p≤0.05) n-6/n-3 ratio were found for the breast muscles of the Pb capons. Both breeds are a good material for production of capons. The meat of the capons of both breeds exhibited a beneficial, higher PUFA/SFA ratio, higher n-3 PUFA and MUFA content, and a more favourable n-6/n-3 ratio.

ABSTRACT The study aimed at investigating which of four traits is the most representative of eggshell strength (destructive eggshell thickness measurement, eggshell weight, egg specific gravity, ultrasonic measurement of eggshell thickness) and could be used for selection purposes. To date, investigations focused mostly on pairwise (eggshell strength vs. another eggshell feature) analyses, resulting in two-, maybe three-trait, models when eggshell traits are considered. Since the covariance estimates are also model dependent, we collected five eggshell traits within one analysis, which better reflects what occurs in nature. The eggs were collected from 4571 Rhode Island White and 2426 Rhode Island Red hens. A multiple-trait animal model and the REML method were employed to compute variance components for calculation of heritabilities and genetic correlations between the traits. On average, the highest correlations were found between the destructive measurement and the other quality traits. It is concluded, however, that the ultrasonic eggshell thickness measurement, also with high genetic correlations with the other traits and leaving an egg intact for further handling, can suit best, as an indirect criterion, the selection for eggshell strength.