The chicken is usually infected between 2-4 weeks of age, before that age they are protected by maternally derived antibodies which protect against colonization.
Ematfole lamasha lasandza kutalwa, lanemaviki lamane kuya kulasitfupha ngebudzala, avame kufihlwa kwentela kuwavikela kuleto tilwane letitingelako, babe bomake bawo bayaluka kudla.