Rooster being aggressive to new hen

[Mo'sMenagerie]

I recently rescued a three-year-old black Australorp hen. She was living alone for a long time. She's a sweetheart. I have four hens and a rooster, all of them around 7 months old. I kept the new girl separate from my flock for about a week, with a couple of days where they were only separated by a fence and could see each other. But now that they're integrated the rooster has not let her come out to eat/drink and chases her when she tries to do anything with the other chickens. Although my hens chased her around a bit, it's been my rooster who has given the new girl the hardest time. I finally separated the rooster from the hens and the new girl is doing much better now.

My concern is if it's okay to keep my rooster away from his hens, and for how long? Today he was away from them for a full day and at the end of the day when I put them back together he immediately jumped on and was very aggressively mating with two of the hens in quick succession. He's very unhappy about being separated. They are all more like pets to me than anything--purely for fun and harvesting eggs, and I don't want to have to rehome my rooster... Will the aggression pass soon? Is it ok to keep him from the hens and let him back in with them at night for a few days? Many thanks for any advice!!

 

[feathermaid]

When you keep a rooster, he will need at least 10 hens to keep everyone from getting over mated and losing feathers on their back. At this age especially, with hormones racing, it's usually the most aggressive time... keeping him separated for a while isn't going to hurt him. He'll just be a whiny baby until he matures. However, not all roosters turn out to be noble flock protectors, you'll have to wait and see how he develops over time.
Here's an interesting article that may give you some insight:

Keeping A Rooster

Good luck with your flock!!

 

[aart]

Welcome to BYC @Mo'sMenagerie !

Couple things you've got going on.
Integrating a single bird can be difficult, good that she was 'accepted' by the pullets.
The mere "couple of days" side by side is not very long for the existing birds to get used to a 'stranger'.(see 'integration basics' below)
Your cockerel is immature and only doing what most young cockerels do. The new hen is probably not submitting to him and he's not giving her time to be wooed. They can also take that frustration out on the pullets.
If you don't need a male bird(to hatch chicks) it might be best to get rid of him, they do often create problems. An all female flock is often much easier, and more pleasant, for a new chicken keeper to deal with. It won't hurt anything to keep him separated 24/7 until you decide what to do long term.

I must mention that bringing in older birds is risky as they can also bring pests and disease, a little late now, but do keep a close eye on her and definitely check her over for external parasites.
-Google images of lice/mites and their eggs before the inspection so you'll know what you're looking for.
-Part the feathers right down to the skin around vent, head/neck and under wings.
Best done well after dark with a strong flashlight/headlight, easier to 'catch' bird and also to check for the mites that live in structure and only come out at night to feed off roosting birds.
Wipe a white paper towel along the underside of roost to look for red smears(smashed well fed mites).


Couple misconceptions to clear up:
The 'rooster' to hen ratio of 1:10 that is often cited is primarily for fertility efficiency in commercial breeding facilities.
It doesn't mean that if a cockbird has 10 hens that he won't abuse or over mate them.
Many breeders keep pairs, trios, quads, etc
It all depends on the temperaments of the cock and hens and sometimes housing provided.
Backyard flocks can achieve good fertility with a larger ratio.

FYI.....semantics, maybe, but can be important communication terms when discussing chicken behavior.
Female chickens are called pullets until one year of age, then they are called hens.
Male chickens are called cockerels until one year of age, then they are called cocks(or cockbirds or roosters).
Age in weeks or months is always a good thing to note.



And might be water under the bridge, but here's some tips on integrations basics that might help you understand chicken dynamics.
Integration Basics:
It's all about territory and resources(space/food/water).
Existing birds will almost always attack new ones to defend their resources.
Understanding chicken behaviors is essential to integrating new birds into your flock.

Confine new birds within sight but physically segregated from older/existing birds for several weeks, so they can see and get used to each other but not physically interact.

In adjacent runs, spread scratch grains along the dividing mesh, best if mesh is just big enough for birds to stick their head thru, so they get used to eating together.

The more space, the better. Birds will peck to establish dominance, the pecked bird needs space to get away. As long as there's no copious blood drawn and/or new bird is not trapped/pinned down and beaten unmercilessly, let them work it out. Every time you interfere or remove new birds, they'll have to start the pecking order thing all over again.

Multiple feed/water stations. Dominance issues are most often carried out over sustenance, more stations lessens the frequency of that issue.

Places for the new birds to hide 'out of line of sight'(but not a dead end trap) and/or up and away from any bully birds. Roosts, pallets or boards leaned up against walls or up on concrete blocks, old chairs tables, branches, logs, stumps out in the run can really help. Lots of diversion and places to 'hide' instead of bare wide open run.

 

[Mo'sMenagerie]

When you keep a rooster, he will need at least 10 hens to keep everyone from getting over mated and losing feathers on their back. At this age especially, with hormones racing, it's usually the most aggressive time... keeping him separated for a while isn't going to hurt him. He'll just be a whiny baby until he matures. However, not all roosters turn out to be noble flock protectors, you'll have to wait and see how he develops over time.
Here's an interesting article that may give you some insight:

Keeping A Rooster

Good luck with your flock!!

Thank you for the thoughtful reply and the link! This is such good info. I do plan to add a few bantams to my flock in the Spring, so I'm hoping I can keep Mr. Rosemary under control until then. So far he hasn't hurt the hens that I have seen. We are starting to keep a super close eye on him, though.