旨在比较海兰灰蛋鸡与海兰褐蛋鸡主要免疫器官(脾脏、法氏囊、胸腺)的发育规律。选取1日龄的海兰灰和海兰褐蛋鸡各138只，按品种分为2组，每组6个重复，每个重复23只，均采用笼养。在63 d试验期内每周从各单元笼随机选取1只鸡测定体重以及免疫器官重量，用于比较2个品种免疫器官发育规律。在此基础上运用Gompertz模型评估3种免疫器官的发育动态。结果:2种蛋鸡免疫器官指数均呈现先增加后下降再趋于稳定的态势。海兰褐蛋鸡脾脏和法氏囊器官指数在28日龄达到峰值，胸腺指数在21日龄达到峰值。海兰灰蛋鸡脾脏指数在35日龄达到峰值，法氏囊指数在21日龄达到峰值，胸腺指数在28日龄达到峰值。品种间比较发现，2种蛋鸡脾脏指数在7日龄和28日龄差异显著(P<0.05);法氏囊指数变化差异较大，在21、42、49、56日龄差异均显著(P<0.05),35日龄差异极显著(P<0.01);胸腺指数仅在56日龄差异极显著(P<0.01)。Gompertz模型拟合结果表明，2种蛋鸡脾脏发育差异不大，其中海兰灰蛋鸡脾脏的拐点日龄为23.460 6日龄，极限重量为2.571 7 g;海兰褐蛋鸡脾脏的拐点日龄为22.077 3日龄，极限重量为2.721 2 g,2项指标均十分接近。海兰灰蛋鸡法氏囊的拐点日龄为16.023 3日龄，海兰褐蛋鸡法氏囊的拐点日龄为7.577 2日龄，前者较后者推迟9日龄左右。海兰灰蛋鸡胸腺的拐点日龄为22.178 1日龄，极限重量为4.209 1 g;海兰褐蛋鸡胸腺的拐点日龄为21.707 1日龄，极限重量为3.807 4 g，二者拐点日龄接近，海兰灰蛋鸡胸腺重量略高。结论:2种蛋鸡脾脏和胸腺发育规律呈现出相同趋势，海兰灰蛋鸡的法氏囊发育晚于海兰褐蛋鸡。

This study aimed to systematically compare the developmental patterns of major immune organs(spleen,bursa of Fabricius,and thymus) between Hy-Line Brown and Hy-Line Grey laying hens. A total of 138 newly hatched 1-day-old Hy-Line Grey and 138 Hy-Line Brown laying hens were selected and randomly divided into 2 groups according to breed,with 6 replicates per group and 23 birds per replicate. All birds were reared in cages. During the 63-day experimental period,one bird was randomly selected from each replicate cage every week to measure body weight and immune organ weights,for comparing the developmental patterns of immune organs between the two breeds.On this basis,the Gompertz model was applied to evaluate the developmental dynamics of the three immune organs. The results showed that the immune organ indices of both breeds presented a consistent trend of initial increase,subsequent decrease,and final stabilization. For Hy-Line Brown laying hens,the spleen and bursa of Fabricius indices peaked at 28 days of age,while the thymus index peaked at 21 days of age. For Hy-Line Grey laying hens,the spleen index peaked at 35 days of age,the bursa of Fabricius index peaked at 21 days of age,and the thymus index peaked at 28 days of age. Inter-breed comparison revealed that the spleen indices of the two breeds were significantly different at 7 and 28 days of age(P<0. 05). The bursa of Fabricius indices showed more substantial differences,with significant differences at 21,42,49 and 56 days of age(P<0. 05) and a highly significant difference at 35 days of age(P<0. 01). The thymus index only presented a highly significant difference between the two breeds at 56 days of age(P<0. 01). Gompertz model fitting results indicated minimal difference in spleen development between the two breeds: the inflection point age of spleen development was 23. 460 6 days with an asymptotic weight of2. 571 7 g for Hy-Line Grey laying hens,and 22. 077 3 days with an asymptotic weight of 2. 721 2 g for Hy-Line Brown laying hens,with the two indicators being very close between breeds. The inflection point age of bursa of Fabricius development was 16. 023 3 days for Hy-Line Grey laying hens and 7. 577 2 days for Hy-Line Brown laying hens,which was delayed by approximately 9 days in the former. For the thymus,the inflection point age was 22. 178 1 days with an asymptotic weight of 4. 209 1 g for Hy-Line Grey laying hens,and 21. 707 1 days with an asymptotic weight of 3. 807 4 g for Hy-Line Brown laying hens; the inflection point ages were similar between breeds,while the asymptotic thymus weight was slightly higher in Hy-Line Grey laying hens.