Today, one of my muscovies finally laid an egg. The bad part is that all the other hens want to make the 2 nest boxes their hangouts. One of the nest boxes became so filled with poo that I removed it, wiped it out and replaced all the hay. I relocated the worst two ducks; they'd just sit around in the box and poop all day. The other 3 (1 of which laid the first egg) stay out during the day, but want to sleep in the boxes at night. Is there any way to keep them from soiling their own nests?