The sentence is:
あの 狐ねばばあに 餌付けでも されたか？
餌付け - is a potential form of the verb.
What role is でも playing here?
餌付け【えづけ】 is a noun derived from the masu stem of a verb. It means "taming an animal by means of feeding it", and it can work as a suru-verb. There is no potential meaning in 餌付け on its own. It's usually not used with a human being, but apparently it's used figuratively here.