Bald patches on the breast of budgie?

It is plucking its feathers.I volunteer at a bird center for abused birds and they said the pluck their own feather's as stress relief,usually due to abuse.You may need to have it seen by a vet so he can give you instructions on what to do because I am only a volunteer and I have not been doing that very long.If you need any other help you can email me at: simba02897@Yahoo.com just tell me who you are and leave your email!Good luck with your bird!My id hear is simba02897 i just joined!