I have a 12x12 chain link chicken run, with 3 feet of hardware cloth up the sides to protect from predators. I have three hens living there. Yesterday, I separated off a section in which to raise 4 6-week-old chicks. The cordoned off section is about 3x3 with 3 foot chicken wire. Last night or this morning one of my three hens flew into the separate section and killed both my RI reds and both my Black Copper Marans. All four chicks are dead. I feel awful. I really didn't think the hens would be able to get over the three foot enclosure. Do I just have one extra-aggressive hen? Is this completely normal? I guess in the future, I'll have to put a roof (and maybe a floor too) on the separate section for the chicks. Any thoughts? I feel like crap.