Influence of live weight and its homogeneity before the beginning of photostimulation on the level of egg productivity of hens

Abstract

Goal. To identify the relationship between the live weight of young hens at the beginning of photostimulation, the homogeneity of the population according to this indicator and the subsequent characteristics of egg productivity of hens of the Ukrainian gene pool population Birkivska barvysta. Methods. The experiment was conducted on hens of the Ukrainian gene pool population Birkivska barvysta for 34 weeks. At the age of 17 weeks, the young birds were divided into 3 experimental groups depending on their live weight: light (1.11–1.35 kg), medium (1.36–1.51 kg), and heavyweight group (1.52–1.90 kg). The control group was a mixed group of birds, not divided by live weight (1.06–1.90 kg). Subsequently, the birds were kept within the classification groups and were evaluated according to egg productivity. Results. The distribution of young animals into groups depending on their live weight before the beginning of photostimulation within certain groups contributed to the increase of homogeneity in this indicator by 16.8–24.1%. With further keeping of hens in equilibrium fractions, the best egg-laying rates were found in the light group — 9.1–12.5% higher compared to other groups and 11.4% higher than in the control group. Due to higher egg production, storability (by 1.1–2.5%), and lower feed costs per 10 eggs (by 11.4–13.7%) they fixed for this group the most profit from each laying hen —1.7–2.4 times more than for other groups, and 2.2 times more than for the control. Increase of homogeneity in some groups contributed to the improvement of zootechnical, productive, and economic indicators in general in comparison to the control: safety — by 1.4%, egg production — up to 4, feed conversion — by 3.7, laying hen profit — by 44% (in 1.4 times). Conclusions. The level of realization of the laying potential largely depends on the live weight of young hens at the beginning of photostimulation and homogeneity in this indicator. This is confirmed by the improvement of egg production not only of individual weight groups (up to 12%) but also of the whole herd (up to 4%). An increase of 1.4 times in the income from one laying hen from equilibrium groups compared to the unbalanced livestock population suggests that keeping laying hens in groups according to their live weight is economically viable.