Ive been doing nuisance control for the last 8 yrs and it sounds to me like you have a coon getting into the crib. I just finished helping a friend, they were losing ducks and everyone said mink but I new better and set a large cage and caught the big male first nite. The killing stopped after that. Just a hunch unless you have seen the mink or weasel Im saying coon. Good Luck trappin