I introduced my 5 younger chickens (4 months old) to my flock of 4 hens (8 months old) about 3 days ago. Every time I checked on them, the little ones were huddled in the corner. Today I found my favorite little hen with it's head pecked to the membrane. The wound is about the size of a nickel. I immediately separated the little ones and brought the wounded one in for TLC. My question is, I heard roosters keep the peace in the flock. Is this true? Or are they just as bad as the rest with new chickens or worse being they can inflict more damage?