Two of our hens hatched nine chicks about a month and a half ago. Everything was going perfect. Mama hens were sharing the responsibility and getting along perfectly, and the other flock members were leaving them alone. Within the past couple of weeks one of the mama hens has turned on her chicks and seeks to peck them even to the point of going into their nesting box at night and just goes after them. Around the same time the rooster has been doing the same. My flock used to get along so well, but now it seems some have just turned mean. The other hens have followed suit and peck them in their nesting boxes. This morning I caught the former mama hen and our rooster outright going after and on top of one of our ducks who always minds her own business so I just can’t understand why. For frame of reference they spend half the day in a free ranging fence and completely free range at night. I would appreciate help if anyone has advise. Thanks so much in advance!