1. Laying hens and broilers of different breeds and ages can suffer from this disease. The earliest incidence can be seen in 3-day-old chickens and 15-40-day-old chickens.
2. The disease can occur all the year round. It occurs frequently in autumn or in the alternation of seasons. It is more likely to occur when the temperature of brooding is low. It is caused by secondary E.coli, enteritis and Newcastle disease.
3. the occurrence of this disease is relatively limited. The majority of the chickens are from the same chicken farm or breed.
4. The disease is a comprehensive disease with complex etiology. When the level of feeding and management is good, it does not occur or the incidence is mild. When there are incentives, it has symptoms of glandular gastritis. Often, after each immunization, the onset or aggravation of the illness occurs.