Katy, it’s hard to know exactly what is going on across the internet but there are a few possibilities. Each chicken has its unique personality, each flock has its own dynamics, and we all have our own unique conditions.
Once a pullet starts laying she generally matures enough to force her way into the pecking order. She might mature enough a few days before she starts or it may take a few weeks after, but generally in that time frame. Until they mature enough to force their way into the pecking order they are on the bottom. It’s pretty normal for a mature hen to peck an immature chicken if that chicken invades their personal space. Usually they handle that by avoiding the adults, just stay away from them. Is your coop or coop/run where you had them big enough for her to stay away from the others?
People like to think it’s age but it’s not. It’s maturity. I’ve had pullets less than five months old join the pecking order shortly after they started laying, I’ve had pullets nine months old not lay and be mature enough to force their way in. Is she laying?
Most of the time if the new chicken stays out of their personal space the hens leave them alone. But occasionally you get a hen that is just a brute. She seeks out an immature chicken and attacks it viciously, even if that chicken tries to avoid it and has a lot of room. You may be unlucky enough to have a brute. Did you notice one hen leading the attack? A possible solution for that is to lock the aggressor up until the new chicken has integrated with the others, then let the aggressor out. Sometimes that changes the flock dynamics and things work out but sometimes it doesn’t. You don’t get guarantees with any of this stuff.
If the pullet is mature enough to force her way into the pecking order she has to force her way in. Sometimes that is not much of a problem, they pretty instinctively seem to know about where they stand. There may be a bit of pecking or even chasing but things work out really peacefully. But occasionally it does involve fighting. The dominant hen or hens in your flock will make sure the new chicken knows her place.
The way chickens have worked out to handle a lot of this is that when there is conflict the weaker runs away. There may be some chasing and maybe a repeat performance but if one runs away they know which is dominant. A huge problem develops if a chicken cannot run away. The winner does not know that they won so she keeps attacking, usually going after the head because that is where they can cause the most damage. The weaker usually hunkers down and tries to protect the head. This can happen if they get trapped against a fence or in a corner. Another problem is that they don’t have enough room to run away and get away. In my opinion the personalities of the individual chickens involved is the most important variable, but you can’t control that. The most important thing you can control is how much room they have. That’s not some square feet per chicken in a coop and/or run, it’s can the chicken get away and avoid the bullies.
Some chickens will attack a strange chicken. They know which chickens belong in their flock and might try to chase any strange chicken away from their territory. They don’t all do this but it happens often enough that it is a real concern.
So if you manage to catch that chicken what can you do? First I suggest you house her next to the other hens across a fence so they can see each other but can’t attack each other. I suggest at least a week. That way they are at least not strangers and aren’t immediately attacked just because they are strangers. They also can sort of access each other’s personalities and place in the pecking order so that might make that process go smoother. It doesn’t always work but it greatly improves your chances of success.
When you do let them mingle give them as much room as you can. That’s not always easy, a lot of us don’t have unlimited room or an unlimited budget to build more room. Some tricks for this is to provide some place for them to hide. Let then get out of the line of sight of the resident chickens. Don’t build traps where they can’t get away but about anything they can hide behind or under. Up high can be a good spot. That might be a table or some type or a roost. When I’m integrating it’s pretty normal for my immature birds to be on the roost when I go down to open the pop door in the morning while the adults are on the coop floor. The roost is a good place for them to avoid the adults.
Another trick is to provide separate food and water stations. Allow her to eat and drink without having to challenge your mature hens.
Don’t force the issue. As best you can allow them to work it out at their own pace. Chickens have been doing this for thousands of years. We cause problems when we don’t allow them to use the things that have worked for thousands of years. We restrict then to small spaces so they can’t get the separation that allows then to work it out.
People think that the problem with introducing one chicken by itself is that the others have just one target to pick on. That’s not what I observed. If you introduce several they will often pick out one specific one to attack while the others are accepted. I think the big problem with a single chicken is that they are social animals, they want to be with other chickens. Instead of them avoiding the adults they are drawn to them, which gets them into that personal space where they get pecked. The same type of thing happens if you try to introduce one older hen to a flock of immature chicks. She is often drawn to them but when she gets there she is a brute to them.
Often this process goes extremely smoothly. It’s so peaceful you don’t even notice it going on. Often you can just add a chicken or a group of chickens to a flock and it goes really well. If that pullet is really mature just adding her to your flock without any type of getting to know each other period often does work. Adding chickens at night so they wake up together does often work, especially if you have a fairly large coop. They work all this out before the human even shows up to know there were issues. But occasionally trying this ends with disaster, dead or seriously injured chickens. The way Dad integrated new chickens was to take them to the coop area and turn them loose in the middle of the day, that is really common. But they totally free ranged. They had all kinds of room. That worked for him, he’d consider all these tricks we use to be silly and unnecessary. But the vast majority of us don’t have that much room so we need to use different tactics.
What works for one person may not work for another or what works once may not work another time. There are just too many variables. I wish you luck in finding that pullet and integrating her.
