Zebra Finch and Yellow Spots

Question
I have had this pair of Zebra Finches for about a year now and one has begun to peck the other on the back of the neck and the beginning of his back. Two yellow spots are almost exposed when he moves around or fluffs his feathers. Other than supplements to help him re-grow feathers, is there any else I can do? I do not know anatomy of birds: What are these yellow spots? I have tried to place the finch with a different mate, but they do not get along well at all. He was born with one of his wings less functional, so he does not fly well, and because of this, is not the dominant of the pair. Any information you can offer would be appreciated!

Thank you!

Answer
Unfortunately, the yellow spots could be anything. I would need a picture in order to give you an answer on what it is.
Zebras are slightly aggressive by nature, this can not be helped. What can be helped is getting your finches used to each other before putting them together. Having them in separate cages side by side is an excellent way for them to get to know each other safely. This will also give you a chance to see any signs of aggression without your little guy getting hurt.
On a side note, zebras that come from breeders are generally more passive than pet store birds. Breeders know know how to care for their birds better than a pet store and will spot problems before they develop into aggression.