A COMPARISON OF THE PERFORMANCE AND SOME PHYSIOLOGICAL STRESS OF LAYING HENS KEPT IN BATTERY CAGES AND ON FLOOR PENS SYSTEM

One hundred and eighty hens 18 weeks old were randomly chosen from a flock reared in deep litter system (from one day old) and used in this experiment. Hens were individual weighted and randomly divided into two equal groups (90 hens each). First group, hens were transferred from floor pens to conventional cages system at 18 weeks of age using 30 cages with 3 birds per cage, each cage considered as a replicate. Second group was still in floor pens with 6 hens per square meter, divided to 3 replicates, each replicate 30 hens, to evaluate the effects of transference hens from floor pens (F.) to conventional cages system (Con.) at 18 weeks of age, compared to others which still in floor pens during the first season of egg production (from 20-52 weeks of age) on productive performance and some physiological stress parameters of laying hens. The main results were as follows: After hens were transferred from floor pens to conventional cages at 18 weeks of age, hens which were still in floor pens had significantly heavier body weight at 20 and 24 weeks of age. Also, feed conversion ratio, egg production percentage and egg weight at 24 weeks of age were significantly (P < 0.05) better. Although, feed consumption was insignificantly higher in conventional cages compared to floor pens system. In general, there was no significant effect between two systems on all parameters that were measured in table (1) from week 28 until week 52. There were significantly (P < 0.05) increased in plasma Heterophil/Lymphocyte (H/L) ratio, serum corticosterone and glucose at 20, 24 and 28 weeks of age for hens which transferred to conventional cages at 18 weeks of age compared to others still on floor pens system. Furthermore, the results of egg albumen and yolk corticosterone concentrations were in same trend of previous results where the concentrations of corticosterone in egg albumen and yolk were significantly (P < 0.05) higher in the hens housed in conventional cages at week 24, 28 and 32 of the age compared to the hens housed on floor pens. Moreover, there were no significant effects of the two housing systems at all parameters that were measured in table (2) from the week 36 until the end of the experiment. From the previous results it could be concluded that hens which transferred from floor pens to conventional cages system at 18 weeks of age were stressed at the start of lay, but adapt to their new environment when hens grew older towards the end of the laying period. Finally, it could be recommended to transfer hens from floor pens to conventional cages system to spend eggs laying period in this system (conventional cages system) which consider much better hygienic standards environment than floor pens system.