my daughter recently got 2 little finches a male and a female..the male is plucking at the female neck and alot of her feathers are falling off...what should I do and what can I do for the sores on the females neck.
It sounds like more than mating behavior. Mallards can be quite aggressive during mating and cause tremendous damage to the head, neck and back of the females, even drowning them at times. But perching birds don't do that.
My guess is he's having territorial issues because the cage is too small or he's just bossy. I'm not sure how bad the injury is to her neck. If it's just irritated, you can keep it clean and it will heal. If she has open sores, I'd recommend taking her to the vet in case she needs medication to avoid a serious infection.
In the mean time it would be good to separate them. Perhaps in time he will adjust to having her nearby and allow her to "visit" in his cage. Or vice versa: put him in a different cage and have him visit in her territory.