I have a Muscovy hen due shortly. I am not sure when as I forgot to write down when she started the clutch. She demanded to use the nest box with the chickens. It is a 15 hole mounted on the wall. She is in the bottom row and second from the end. She is holding the nest tight. I noticed I have a few chicken eggs in the nest. They are brown in color. I been trying to get them away from her as I don't want her to quit the nest when they start hatching earlier than the duck eggs She has a khaki egg or two which should hatch at 28 days. Then she has Muscovy eggs that the khaki male is father to. Those should go to 35 days. I have a incubator in the house currently running and a box with heat lamp, set up for the newly hatched babies. I tried getting the brown eggs away from her this afternoon and she nailed me hard with her beak and left a mark on the back of my hand. I think the chicken eggs maybe infertile as I only have the 2 small roosters and I doubt they are getting to all the hens. So I just probably may have to let mother nature do her thing and have some patience with this duck.