I have a 8 month old mallard drake. Yesterday when I went out to feed a clean up their pool I noticed one of them had a swollen chest and was walking funny. He is not eating and is very lethargic. I thought that maybe he has a impacted crop but I am also under the impression that that only happens to chickens. I gave him some olive oil in his water and massaged his crop but other than that I don't know what to do. I called every vet in town and nobody treats ducks which is frustrating. Please help if you can.