We have 2 , 1 &1/2 year old hens that we've raised from chicks. They've been living in peace and harmony since the beginning. That has recently changed! Out of nowhere the boss of the 2, "Big Mama" decided to attack the other for no apparent reason. We have continually broken up the unprovoked , vicious attacks and separated the bully from the other, however she continues her behavior when we put them back together. They have sufficient space in their coop and are allowed many daily hours of free range time. I am afraid that "Big Mama" will kill the other. She does not back down and the other chicken is very timid and will not fight back. I've monitored them and have found no signs of sickness or disease in either hens. Any tips or advice as what to try next? I love these 2 chickens They have always been so sweet. They love to follow us around the yard and even jump up on our laps occasionally. I would love to FIX this new bizarre problem.