| A large number of previous research have proved that a large enriched or furnished cages can improve hens' welfare condition much better than a small enriched cage.However,the large enriched cages were found to have more cracked or dirty eggs than the smaller cages,this leads to loss of profit due to poor quality of eggs.Clearly,the question of poorer external egg quality due to occurrence of more cracked/dirty eggs is attributed to the defect of cage design,and it may also indicate that the group is too large to influence the utilization of the nestbox.Although this phenomenon exists generally,the internal causes leading to the poor quality of eggs is not entirely clear.In order to tackle the problems of poor external egg quality in large enriched cages,the project aims to study the preference of laying hens for nestbox,the effect of the social states of hens on their preference and the effects of optimization of nestbox distribution on the external egg quality.Through the observation of the preference for next position,the tendency of selection for preferred position can be determined.And then by setting different group sizes we can determine the effects of the grooming of sociality of individuals on position selection and the utilization of the nestbox.Based on the results of production and welfare parameters,with combining the preference of next position and the effect of the sociality on the preference,we test the minimized effects of such combination on the external egg quality.The results of this study will provided valuable information for better design of large enriched cages improving the external egg quality.Test 1: The purpose of this experiment is to study the influence of the size of the cage,the position of the egg box and the cover of the egg box on the phase of the enriched egg and the preference of the egg box.The experiment selects 18 weeks laying hens of 1800 weeks.In the cage,the egg box in the cage is arranged in the upper seal,the upper semi closed,the lower layer and the lower half closed.There are 8 processes in total,and 3 repetitions per treatment.The average number of visits to egg boxes,the average number of penguin gestures and the rate of dirty eggs were observed.The results show that the size of the cage has a significant influence on the average access times of the egg box(P<0.05),which shows that the average access times of the egg box in the medium cage is significantly higher than the large cage(P<0.05).The average access of the shelter to the egg box is the average access times of the egg box.The effect of cage size on the average number of penguin postures was not significant(P>0.05).The average number of penguin posture was significantly higher than that of the non closed type(P<0.05).The average number of penguin posture in the upper egg box is significantly higher than that in the lower egg box(P<0.05).There was no significant difference in the influence of cage size,egg box location and egg box covering on the rate of dirty eggs(P>0.05).Test 2: The purpose of this experiment is to optimize the egg box configuration,and the effect of different enrichment and cage environment on performance,egg quality and welfare index of laying hens.The experiment selected large enrichment cages(60 / cages)and medium concentration cages(15 cages)as the experimental group,and the parallel control was repeated in the traditional chicken cage group(4 / cages)each.The egg box in the enrichment cage is set up,and the upper closed type is selected.The detection of different enrichment cage environment on the performance of laying hens,egg quality,behavior and welfare effects.The results showed that the laying age of laying hens in the large concentration cage is 19 weeks old,the medium-sized cage is 18 weeks,and the traditional cage is 18 weeks.The maximum egg laying rate of large cage is 83.66%,the middle cage is 93.62%,and the traditional cage is 95.83%.At the age of 30 weeks,the hirson unit of eggs in large enrichment cage was significantly higher than that of the control group(P <0.05),and there was no significant difference between the large enrichment cage and the large enrichment cage and the traditional cage group(P>0.05).The eggshell strength of eggs in the large enrichment cage was significantly higher than that in the control group at 38 weeks old(P<0.05).The feather score of traditional cage group at 22 weeks old is significantly higher than that of large enrichment cage(P<0.05),but there is no significant difference between mediumsized cage and control group.The gait score of large cage group was significantly lower than that of traditional cage group(P<0.05).The walking behavior of layers in the large enrichment cage was significantly higher than that of the control group(P<0.01),while the proportion of standing and lying down was significantly lower than that of the medium enrichment cage and the control group(P<0.01).The feather picking behavior,comfort behavior,drinking behavior,modifying behavior and fighting behavior of layers in the large enrichment cage were significantly higher than those in the middle enrichment cage and control group(P<0.05).The conclusion of this experiment is that the size of cage,the position of the egg box and the shielding situation have no significant influence on the cage visceral egg rate.The number of access times and the number of penguin positions in the upper closed type egg box is significantly higher than that of the other type of egg box,and the laying hen is more inclined to choose the egg box of the upper closed type.The egg laying rate of the large enrichment cage is lower than that of the medium-sized enrichment cage,but the egg production rate of the traditional cage is significantly higher than that of the large enrichment cage and the medium-sized enrichment cage.The feather score of traditional cage is significantly higher than that of large enrichment cage and medium-sized enrichment cage.The enriched hens were more abundant in behavior,providing more opportunities for walking behavior and behavior,showing more comfort. |
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