Adding Just 1 Chicken To The Big Chicken Coop

We have 1 leghorn hen that needs to be added to the big coop with the other bigger chickens. We got her in November with her 4 leghorn siblings. They were all about 1-2 months old I believe. Since then 2 of them didn't make it.
About a month ago Teeny, I call our leghorn hen, became malnutritious. She's always been the smaller one and I'm guessing her siblings started keeping her from getting enough food. I found her one day laying in the little coop and thought she was dead, she laid on her side for days and couldn't even sit up. When I found her I took her inside for 2 weeks and kept her in a dog crate until she was able to walk around some then. She was walking very well except it was kind of like she was drunk because she crossed her legs.
Anyways, since then, her remaining 2 siblings were added to the larger coop, and now that she's back outside and in the little coop by herself, running and even perching again, I'm wondering how to go about adding her to the big coop eventually??
I think she should be about 4-5 months old now. The big coop currently consists of 7 chickens: 4 roosters & 3 hens. I know for sure that 5 of the 7 chickens are 1 year or less.

HI - and welcome to BYC!

One thing you can do is set up a wire enclosure inside your run and inside your coop at night. Let her start being with the flock where they can see her but not touch her. Once they start ignoring her, you just open the door and usually she'll fit right in. Sometimes if you have another mellow chicken, you can introduce them first and then to the others later.

Good luck on whatever you decide!

Awesome! Thanks!
The little coop is kind of built onto the big coop like an extension. They actually share a chicken wire wall.
Mostly I was worried about them bullying her again and squishing her or something.
Thank you so much!

A ratio of 4 roosters to 3 hens is a recipe for overmating of the hens and likely bloodshed between the roosters. You might not have problems now if your birds are less than a year but beware. Expect serious conflict ahead.

I really hate to do this, but I'm going to point out something that you probably haven't thought about.

For Teeny not to have gotten enough to eat and becoming sick from malnutrition, there was probably something wrong with her health that the rest of the flock picked up on and is the reason why they may have kept her from the food. It's the way of chickens, having an instinct to keep the flock strong and wanting to drive away any chickens with problems.

You mention she still walks funny. The flock will pick up on any abnormality and will most likely pick on her, and unless you keep her separate and feed her separately, the exact same thing is most likely to happen all over again. They mayl intimidate her to the extent she will be afraid to eat.

You can try gradually re-introducing her to the flock, but you need to be aware that they may never accept her as long as she's not completely normal.

I'm sorry for both Teeny and you. It's not easy dealing with a disabled hen you really love. You might check out Gita's thread on caring for disabled chickens. I'll be back to edit a link to it. https://www.backyardchickens.com/t/1075428/disabled-flock-members

We are about to get rid of 2 roosters.

She never walked different before she got sick. The weird thing was, to me, was she was fine one day and the next morning I saw she couldn't sit. It's like it happened over night.
She really doesn't seem to walk very different anymore.

Nevertheless, keep a close eye on her, because the other chickens may have noticed something wrong that we wouldn't pick up on. Introduce her back to the flock gradually, making sure you feed her separately for the next month, and when you do begin letting her share the communal feeder, check her crop regularly to be certain she's getting enough to eat.

Like I said, she may need to be segregated permanently if she isn't permitted to eat with the others.