Feather loss on one finch

Question
I have two male society finches and one has lost most of his tail, and one wing. The other one is fine, it's been two months and no growth. I was thinking mites but the other one has nothing wrong with him, I have a UV light, big four foot long cage for flying and great food, egg shell, veggies and garlic herb. My guys get their  cage cleaned every day faithfully before I go to work, and once a month I use bleach. I think I'm doing everything right just don't know why my little guy is not growing his feathers, can you help?

Answer
It may be mites and the other just hasn't caught it yet. A good way to tell is by the condition of the remaining feathers. The best feathers to check are the wings. If the wing feathers have gaps and are poorly cared for, they have mites. This can be treated with products from www.ladygouldian.com. The owner is knowledgeable on finches and will be able to help you which product to use and how to properly use it.
It's also a possibility that the birds are under nourished. Is their food fortified with nutrients? Again, products to help with that can be found on the site above.
Another possibility is that the other male is picking on the featherless one. Watch the cage carefully (try not to let them see you watching their cage. Birds behave differently if they realize your looking). It may be necessary to separate the two if one is picking on the other.