Mongeese donʻt really bother adult chickens, but they love to steal their eggs and terrorize them. They do love to kill young chickens. They can burrow, how fast depends on softness of the soil. Also if it is level or bumpy. Gotta have a trap going all the time and catch those buggas. Itʻs part of farming. Babies freak out and will stick their heads out of the chicken wiire and lose their head. But again, thatʻs just for the babies. I hate mongeese, I am at war with them for killing my special Cream Legbar chicks.