Did my rooster kill my chicken? Need advice.

[EldritchAnomaly]

Hello. This is my first time posting here and my first time raising chickens. I brought 5 sexed chicks home and have raised them to 12 weeks old without issue. I have them in a 4x3 coop attached to an 8x8 covered run that I built. Around 12 weeks old, I was given a rooster (5-6 months old) by a family member. I thought that he was too old for them and might hurt them, but they assured me it was fine. That was 2 weeks ago. I've noticed him trying to mount them at least twice and my hens have seemed reluctant to leave the coop the last few days. This morning I found one of my females dead in the coop. Ants made determining cause of death difficult. How likely is it that the rooster killed her? We are returning the rooster for now since I have nowhere else to put him.
Thank you for any advice you all can give me.

 

[sourland]

It is very possible that the rooster inadvertently killed the pullet while trying to breed; however, I would check carefully to make sure no predator is able to access the coop. Sorry for your loss.

 

[Saveria]

Welcome to BYC.

Not likely if you never saw excessively aggressive behavior from him before. Possible, yes. Likely, no. That sounds pretty normal for a mature rooster with almost mature pullets.

Did the ants just get to her super fast, or was she dead there for a little bit? I'm not sure we can tell if you can't examine her, but chickens usually shed blood when they kill each other, and it takes a bit. I imagine a rooster could snap a neck so it was a clean death, but I have never heard of that happening.

 

[Tonyroo]

To me it's possible for a older cockerel to kill a very young pullet. Knowing how they behave during there raging hormone stage of life.

You did the right thing returning him. And try to keep the ants away from the chicken area, you can use agricultural lime to keep it under control.