I had just let my 11 hens (1 swedish flower hen, 1 barred rock, 1 lemon cuckoo orpington, 1 australorp and 5 buff orpingtons) and rooster (lavender orpington) out of their coop to rummage around the yard. Shortly after i let them out the rooster strangly ran after my SFH around the yard, she clucked unhappily until i got in between them.then, I sat down to watch them because it was fairly warm. I saw the rooster, the SFH, and the australorp rummaging through the soft soil under an empty rabbit hutch, but then, the australorp puffed her neck feathers and in response, so did the rooster. He's roughly over a year old and she is going on 3-4 years. They started kicking and trying to bite. At this point, I get concerned for the hen (she's the only hen right now thats laying eggs and is concidered my broody hen, the others are getting there) and try to split them up. She ends up running away from him and he chases her. She attempted to give up and did the submissive squat, but he kept tearing and kicking at her. She even jumped on a perch and he was still trying to get at her. eventually i caught him and separated him from her for about 2-3 hrs. he crowed almost in defiance 15 times or more in succession. Later i let him back out, thinking the squabble would be forgotten and all would be fine. I watched him for 15 minutes before i returned inside. I come out an hour later 'cause i heard the rooster clucking like he had seen one of the rodents that's been lurking under our compost pile and i see my australorp perched on the coop door with a bright red bloodied comb. the rooster and the other hens were 50 feet away in our garden. So i secluded her so she could recuperate and treated her comb. I've never seen him be aggressive before and it worries me, he seemed rageful. If anyone has experienced this before or has had rooster experience please help me with some advice. And could a health issue or bugs cause a change in behavior?