my paraketet is lossing feathers

by nikollas
(brooklyn, new york, United States)

hi i have three different parakeets and they are all in the same cage. the question i wanted to ask is that there feathers all over there body looks dirty and in the last couple of days they are shedding feathers alot. i can even see loose feathers. There is no bald spot on them thought. please help i don't know if they are sick or not.