Effects of Production Performance, Immunity and Egg Quality by Raising on Exercise Yard in Laying Hens

Abstract

The present study examined effects of production performance, immune activity and egg quality by raising on exercise yard in laying Hens, the results of which could be used as baseline data to enhance animal welfare and the safety of livestock products. A total of 90 Hy-line-Brown laying hens of 13 weeks old were used in the experiment for 38 weeks. The cage group (Cage group) was raised in a cage, where an area of 0.084 m 2 was assigned to two hens, while hens in the exercise yard 1.1m 2 group (1.1 m 2 group) was assigned to a combination of a chicken house (0.11 m ) per a hen. Treatment was replicated 3 times with ten birds per replication. Ten birds were arranged according to randomized block design. While initial egg production rate was significantly higher in the Cage group, 1.1 m 2 group exhibited a slightly higher rate in the mid-and late-stage of the experiment, although the difference was not statistically significant. Exercise yard treatment groups exhibited a higher feed intake rate than the Cage group up until the hens were 39 weeks old (P<0.05), but the difference dissipated from that age on. The age at first egg in the exercise yard treatment groups was 16 days later than that for the Cage group (P<0.05), although differences in the quality of the eggs were not observed. The results of immune activity test showed that IgA in the exercise yard treatment groups was significantly higher than that in the Cage group (P<0.05). IgG, IgM, and corticosterone were also higher in the exercise yard treatment groups. The soil in exercise yard increased of organic matter and decreased of cation exchange capacity (CEC) in raised hens. In sum, raising hens in a exercise yard raise style decreased the rate of initial egg production, which was followed by a slight increase during the latter part of the experiment. The exercise yard raise hens' immune activity was heightened.(Key words : laying hens, animal welfare, immunity, stress, egg production) † To whom correspondence should be addressed : kimkisoo@korea.kr