If they have no bad smell to them when you crack them open I would think they would be safe for the dog. I let mine sit on the counter uncleaned for over a month at a time with no problems at all and they don't hurt me so that is where I am coming from. They are in an egg carton, not just laying dirty on the counter.33!!! From five ducks! One who is broody and sitting tight!
29 of which I cleaned out from under the trailer... Found where they were stashing them before I confined them!
Now I'm wondering how old they are and if I should crack them open and freeze them for the dog... Some are really filthy.