I had about 20 Muscovy eggs in the bator and I just candled them and none were good. Most have been in for 25 days, so i figured I would check for rotten ones. I found one bad one, and the rest are clear. i even broke some open to check. I'm was really hoping for some baby ducks, I guess I have to wait. On the other hand, i candled two chicken eggs i had in there and they are doing good.