What is the cause of a large amount of hair loss in the pigeon

A large amount of hair loss of pigeons indicates that it is necessary to change the feather, or there is a problem with health.Usually, the birds will slowly lose hair in July of the lunar calendar each year. They basically lose light in August. New feathers will grow in September. It can grow well in October.However, their hair changing period is also affected by many factors, and sometimes the phenomenon of delay in hair change is also normal.The hair loss caused by health problems is often a lack of nutrition, and pay attention to replenishment in time.