The effect of caponization on the mechanical properties of Polbar chicken bones was the subject of investigation. The biomechanical strength of bones

This study aimed to develop a methodology for using ultrasonic technology (USG) to record eggshell thickness for selection of layers. Genetic correla

For many generations, most species of farm animals have been subjected to intense and strictly targeted selection for improvement of their performance traits. This has led to substantial changes in animal anatomy and physiology, which resulted in considerable differences between the current animal breeds and their wild ancestors. The aim of the study was to determine whether there is breed-specific variability in behaviour as well as differences in emotional reactivity and preferences of laying hens. The investigations involved 50 Green-legged Partridge, 50 Polbar, and 50 Leghorn hens. All birds were kept in the same conditions, and the behavioural tests were carried out at 30 weeks of age. We used the tonic immobility test and a modified open-field test including such objects as water, commercial feed, feed enriched with cereal grains, finely cut straw, and insect larvae, a sandpit, a mirror, and a shelter imitating a hen nest. The research results demonstrate that the birds of the analysed breeds differ not only in the excitability and emotional reactivity but, importantly, also in the preferences for environment-enriching elements. Ensuring hens' well-being should therefore be based on environmental modifications that will facilitate acquisition of essential elements of chickens' behaviour. The greatest emotional reactivity was found in the Leghorn breed, which may be a result of correlated selection aimed at an increase in chicken productivity. The differences in the behaviour of the birds from the analysed breeds indicate that laying hens cannot be regarded as one group of animals with the same environmental requirements.

The aim of this study was to evaluate the indicators of the behavioural and physiological welfare of Japanese quails (Coturnix japonica) as possible responses to the enrichment of the birds’ habitat. The study sample consisted of 280 Japanese quails (224 ♀ and 56 ♂, respectively). Birds of 5 weeks of age were randomly divided into seven equally sized groups and then divided into replication subgroups (four per group, 10 birds in each replication). Birds were maintained in 0.5 m² cages with unrestricted access to water and food. The experimental factor was the presence or absence of enrichment of the birds’ cages: the nest box, scratcher, plastic corrugated pipe (tunnel), limestone cubes, sandbathing box and feeder box with a drilled cover. Quails were subjected to behavioural tests (tonic immobility and open field tests) and, after 6 weeks, blood samples were taken from them to determine their biochemical indices as well as their cortisol and corticosterone levels. An additional element was the assessment of fertility indices. The presence of enrichment was shown to reduce behavioural disturbances in Japanese quails. This study also found that the colour and shape of an object were very important regarding the birds’ interest in it. Additionally, individuals kept in enriched cages, who were allowed to exhibit their natural behavioural patterns, had lower stress levels.

The aim of the study was to determine daily changes in some egg quality parameters, indirectly reflecting egg freshness, and to assess the possibility of predicting time from laying using mathematical methods. The study material consisted of 365 table eggs of medium (M, ≥53 g and <63 g) and large (L, ≥63 g and <73 g) weight classes (commercial stock, cage system, brown-shelled eggs) collected on the same day. Eggs were numbered individually and placed on transport trays and stored (14 °C, 70% RH). Every day, for 35 days, egg quality characteristics were analyzed (10 eggs per group). The change of traits in time was analyzed on the basis of linear and polynomial regression equations, depending on the trait. Based on model fitting, eight traits were selected as those most affected by storage time: egg weight and specific weight, Haugh units, albumen weight, air cell depth, yolk index, albumen and yolk pH. These traits, excluding those related to the weight, were then used in a multiple linear regression model to predict egg age. All regression models presented in this study were characterized by high predictive efficiency, which was confirmed by comparison of the observed and estimated values.