The aim of the study was to evaluate the relationship between the eggshell color parameters and its mineral composition as well as the internal quality of eggs derived from various breeds of hens, varied by eggshell color: seledine from Araucana, brown from Marans, and white from Leghorn. The sample consisted of 180 eggs (60/group) The eggshell color was measured using CIE L*a*b* system. The quality evaluation included traits of whole egg (weight, specific gravity, proportions of elements, shape index), yolk (weight, color, index, pH), albumen (weight, height, pH), and shell (color, strength, weight, thickness, density). The mineral composition of eggshells was analyzed. The eggs origin affected the quality characteristics of particular egg elements (p < 0.001). However, the impact of analyzed colors on the egg quality traits varied, and in the case of whole egg and albumen traits the most favorable was the white color (p ≤ 0.05), while in the case of the strength of shell or its thickness it was the dark brown color (p ≤ 0.05). The eggshell color influenced variations in its mineral composition (p < 0.001) except potassium and sodium content, while the proportion of particular mineral elements in shell was correlated with the L*a*b* color space coordinates (p ≤ 0.05).

The sample consisted of 480 hatching eggs of Japanese quails and was divided into 4 groups. Before the transfer to the incubator, the first group was not disinfected (negative control). In the second group, eggs were disinfected by means of formaldehyde fumigation (positive control). In the third and fourth group, reactive oxygen forms were used for disinfection- perhydrol (H2O2) and ozone (O3), respectively. Eggs were incubated under standard conditions. On the 14th D, eggs were candled, and proportions of fertilized eggs and died embryos were calculated. In addition, samples were collected for microbiological examination. After 17.5 D, the results of the whole hatching were evaluated. Chicks were reared for 14 D. Their survivability and body weight gain were recorded. Disinfection by means of reactive oxygen forms did not prove to be more effective in reducing the number of bacterial colonies on the shell. Reduced hatching and significantly increased mortality in the O3 group may indicate the negative impact of this gas on developing embryos. The results of hatching from eggs disinfected with H2O2 did not differ from those obtained in control groups. The biggest chicks were obtained from O3 disinfected eggs. However, during rearing, their growth did not match the one observed for birds in the remaining groups. Chicks hatched from eggs disinfected with H2O2 were characterized by the largest survivability. Disinfection with reactive oxygen forms did not significantly improve the hygiene of hatching eggs, hatching performance, and quality of hatched chicks. Hydrogen peroxide, whose application offered satisfactory hatching results, may be the recommended disinfectant. On the other hand, O3 appears to be undesirable because of its negative impact on bird embryos.

The aim of the study was to assess the influence of shell defects on the quality of eggs after storage. The study material consisted of 1,800 brown-shelled eggs from cage rearing system which were candled on the day of laying to determine the shell quality. Eggs with the 6 most common shell defects (external crack, severe stripe marks, points, wrinkled, pimples, sandy) and eggs without defects (control group) were then stored for 35 days at 14°C and 70% humidity. The weight loss of eggs was monitored every 7 days, and the quality characteristics of whole eggs (weight, specific gravity, shape), shell (defects, strength, color, weight, thickness, density), albumen (weight, height, pH) and yolk (weight, color, pH) of 30 eggs from each group were analysed at the beginning (0 days) and after 28 and 35 days of storage. The changes resulting from water loss (air cell depth, weight loss, shell permeability) were also evaluated. The study showed that all investigated shell defects significantly influenced the characteristics of the whole egg during the storage, modifying traits such as specific gravity, water loss, shell permeability, albumen height and pH, as well as proportion, index and pH of the yolk. Furthermore, an interaction between time and the shell defects presence was found.

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.

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.