Fighting In Hens

I opened the coop the other day to find that my beautiful Mackenzie, of undetermined breed, was missing a few feathers. I dismissed it and decided to watch them a bit more closely.

That was a few days ago.

This afternoon I'm outside fixing the back fence with my older sister when she turns and starts yelling. I'm surprised but I can't make out a word she's saying.

She drops a board of wood and points to my chickens.

When I turn, my biggest chicken, Keisha, has Mackenzie pegged against the side of their coop and has a firm grip on her neck.

Naturally, I turn and run towards them, screaming at them to stop. They don't separate until I get in there and pull them apart.

As we speak, I've separated them from eachother. Mackenzie and the other chicken, Beatrice- a red sex link- are in the coop while Keisha is in an old cage we had because it was all we could do.

They've had scuffles- or little fights- that I mistook for playing. They've never gotten vicious before that I've known as and Beatrice, the smallest of the entire bunch at almost half their size, has never been involved. She's very tiny at atleast thirteen weeks old, same age as the two bigger two, but always manages to stay out of it.

Could this be because of her size? My older sister said that it might be because she's a lot smaller and not seen as an opponent.

I'm very curious as to what you all think because I love all my chickens so much and raised them since they were all a week old so I've grown very attached. Have any of you experienced this and how have you dealed with it?

[As we speak, I'm planning to keep them apart for atleast two days just to see if that solves their problem.]

Thanks in advance,
Rachel.