青年鸡

该病主要侵害3～12周龄的雏鸡与青年鸡，破坏法氏囊中的B淋巴细胞，导致不同程度的免疫抑制，从而使病鸡增加对并发和继发性病毒和细菌感染的易感性。

B-lymphocytes are destroyed by IBDV infection , followed by-severe immunosuppression which increases susceptibility to other disease in young chickens at 3-12 weeks of age .

这就是：对青年鸡至少进行2次ibd免疫。

That is to vaccinate a pullet flock at least twice for IBD .

传染性法氏囊病（IBD）是由传染性法氏囊病毒引起的高度接触性传染病，主要感染青年鸡。

Infectious bursal disease ( IBD ) is an acute and contagious viral infection of young chickens caused by IBD virus ( IBDV ) .

青年鸡与产蛋鸡易地专业化生产系统的研究

Study on the Specialized Production of Pullets and Laying Hens in Different Places

对刚出壳雏鸡与青年鸡的红细胞免疫粘附功能进行了比较，结果表明：刚出壳雏鸡红细胞免疫粘附功能明显低于青年鸡；

The study compares the immune function of chicken erythrocyte between the young and the adult .

鸡伤寒是由鸡伤寒沙门氏菌引起的，以肝、脾等实质器官的病变和下痢为特征，发生于成年鸡和青年鸡的败血性传染病，该病既可水平传播，也能垂直传播。

Fowl Typhoid is caused by salmonella typhimurium , with the characteristic of liver , spleen and other essential organs lesions and diarrhoea , which is a septic infectious disease that occurs in adult chicken and young chicken .