ASABE Technical Library - Abstract

Abstract. The aim of this experiment was to investigate the effect of group size on mating behaviours of males and to identify the relationship between age variance and behaviour & fertility change. Jing BrownⅠlayer breeders were housed in group size of 100 and 200 hens (100F and 200F) in perchery systems with a male to female ratio of 1:10. Behaviour observations were conducted four days per observation week (14:00~15:00, 15:00~16:00 and 19:00~20:00), respectively at 36 weeks, 40 weeks and 44 weeks of age.

Frequencies of mating and wing flapping were significantly affected by group size and bird age. A remarkable higher frequency of mating was found in 100F groups in comparison to 200F (P=0.002 for 36 weeks and P=0.031 for 40 weeks). And only at 36 weeks, frequency of wing flapping in 100F was significantly higher than 200F groups (P<0.001). Ages negatively impacted mating behaviours, as mating frequency declined with age in 200F groups (F_{2, 9}=2.391, P=0.147). And matings and wing flappings were displayed fewest in 40 weeks, significantly varied from 36 weeks (P<0.01) in both group sizes. Fertility decreased with group size and was not affected much by age variance. No significant differences of average mating duration were detected in different groups (F_{1, 22}=2.397, P=0.136), and completeness of mating was better in small flocks. For site selection, aisle and the area nearby were preferred mainly because males spent most time there. And for which we can tell that males in groups of current sizes were passive for matings. No specific relationship was identified between mating behaviours and fertility. More detailed observation both about males and females in a longer production period should be performed to bring confirmed conclusion about the effect of group size on mating behaviours and fertility.