| With the increase of labor cost and social concern for domestic animals' welfare in China,it is difficult for the further development of traditional artificial insemination for layer breeders breeding.Impressive advantages of three-dimensional system(TDS)in saving labor costs,reducing stress of animals,increasing stocking density(SD)and animal welfare,make it be in line with the development direction and needs of the transformation and upgrading of housing systems for layer breeders.By exploring the influence of spatial allocation,forms of multi-tier structure,parameters of SD and GS on birds' distribution and behaviors,this study systematically analyzed the relationship between behaviors of layer breeders and configuration of facilities and equipment,so as to provide theoretical and data support for the establishment of TDS for layer breeders.The main research contents,results and conclusions were as follows:1.Effect of space allocation on spatial adaptation of birds.This part investigated the effects of the time(63 days of age-63P+,73 days of age—73P+)to add perches,the location of added perches and the spatial allocation(by adding ramps—ramp group,by adding ladders—ladder group)of TDS(with 4-tier,S4)on birds' spatial adaptation in the TDS.1.1 The ratio of pullets feeding and roosting increased in cages with perches.After transferred into ramp groups,the proportion of 63P+ birds distributed in the upper space at the initial stage of adaptation was higher than that in 73P+ group and significantly higher than that in the control group,indicating that the time of adding perches had significant effects.1.2 Significantly more birds in ramp group used the upper space than ladder groups,suggesting that traffic convenience between tiers affects stereo space utilization and distribution of birds and we recommend ramps for use with angles no more than 40°.1.3 In the early stage of egg production(22-25 weeks),the proportion of floor eggs in ramp group was significantly lower than that in ladder group(P<0.001),which was attributed to earlier exploration and utilization of upper space in ramp groups.2.Effect of SD on layer breeders' behavior,distribution and health.Three hundred and twenty-four Jing Brown No.1 parent flock were divided into 4 groups(SD:18 birds/m2 and 24 birds/m2,each with 2 replications)and take records of birds' distribution,behaviors and health condition in TDS(with 3-tier,S3).2.1 The proportion of hens distributed in nest boxes and upper perches in high SD groups was significantly higher than that in the low SD groups.The distribution of cocks was not affected by SD and they mainly stayed on the system floor.2.2 The proportion of feeding duration of individual female decreased with the increase of SD,while the proportion of standing duration increased.Individual behaviors of cocks were not significantly affected by SD,and standing behavior was the primary one,accounting for 51.1%?61.1%.More gentle feather pecks towards the back of hens and aggressive pecks towards exposed skin was found in high SD group.2.3 The influence of age on birds' health condition is greater than SD:health condition of birds significantly reduced with age.At the age of 61 weeks,only the feather coverage on the back of hens with natural mating was significantly inferior than that of caged hens and it could be speculated that mating behavior is the main reason affecting the damage of back feather.3.Characteristics of mating behaviors in TDS and the effect of GS.Six hundred and sixty Jing Brown No.1 parent flock(male to female ratio 1:10)were divided into 4 groups,of which 110 birds per group and 220 birds per group were duplicated twice respectively.Group mating behavior was observed at the age of 36,40 and 44 weeks,and the fertility was tested at the end of each age.During 44-46 weeks,mating behaviors in both GS groups were observed for 5 consecutive days(6 h per day).3.1 The mating frequency and completeness were higher in small groups than that in large groups based on intermittent observation,and mating frequency of both GS groups decreased with age.However,the fertility remained above 93%during the whole period and there was no significant difference between different GS groups.3.2 Continuous observation showed that more than 90%cocks participated in mating,but the mating frequency between individuals varied greatly.3.3 More than 95%mating behaviors occurred on the system floor in TDS,mainly in the open areas.4.The influence of multi-tier structure optimization and the utilization of welfare facilities.4.1 Observation on the activity path of birds and range use of marked hens in S4 system showed that there was low probability of home range crossover of hens on top platform and cocks,inferring that was there was a lack of socialization between hens and cocks.4.2 After blocking the entrance of the top platform in S4 system,the range use of hens on the top platform shifted to the lower areas,covering the main activity area of cocks.We suggest that the number of platforms including the system floor of TDS for layer breeders should not exceed 3 tiers.4.3 The utilization uniformity of the double-decker nest boxes in S3 system increased with age from 21 to 23 weeks of age and the overall utilization ratio and utilization uniformity still needed to be improved.4.4 Distribution of hens in S3 system was continuously monitored by using the monitoring system of birds on perches.Results showed an obvious circadian rhythm of perch use,with the largest number of birds roosting on perches at night,accounting for 37.5%?44.3%.The utilization pattern of perches at different positions was different. |
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