Abstract: The objective of this study was to approach the effect of different additives on performance of laying hens. One thousand five hundred 280\|day\|old healthy Hyline laying hens were randomly divided to five treatments with five replicates for each and sixty hens in each replicate. The control group was fed with the corn\|soybean meal based diet， and the treated groups were added by 0015% hydroxytetracline， 001% microeco\|preparation， 01% Chinese herbal medicine extractive， and 5% biologic complex mixture on the basis of the control group respectively. We investigated the effect of different additives on performance and egg quality of laying hens for 30 days. The results showed that the groups added with microecologics， Chinese herbal medicine， and complex mixture significantly increased egg quantity and egg weight， improved the contents of cholesterin， ash， protein and the egg thickness. The results indicated that basal diet added by 5% biologic complex mixture can increase the performance of laying hens and showed a better egg quality.

Key words: biologic complex mixture, microecologics, Chinese herbal medicine extractive, laying hen, performance, egg quality