Mine will cover all f their eggs if no other hens try to lay in their nests. Eggs tend to get displaced when there are multiple hns on one nest.My Muscovies have never on purpose rolled an egg away actually never found an egg out of their nest once they start to brood. Haven't had my Runners or Buffs go broody so can't say on them. I have had Muscovy since 2004 and nope never once.

X2I had an egg explode under a broody once. NastyThat's why I candle eggs under broodies now, lol.