I came out to feed this morning and found one of my ducks sagging her head. One side of her face is swollen and it looks like she's missing a eye! i know shes in pain and all she wants to do is hide and hang her head. What should I do? They are free range so anything could have happened.my husband thinks it's a snake bite. I have given her 1\2 ml of children's benadryl and put her in a warm dark place and have been giving her water every hour or so with a dropper.