Persistent vent pecker??

[LtDanFan]

the other day, i noticed blood in the nest box and more blood on the eggs than usual. I figured out which hen it was based on the fact that she had blood clots and her vent was actively being pecked by other chickens.
I spearated her. She has slept in a cardboard box in my house for the last 3 nights because i wanted to make sure she was ok and i didn’t want her to get pecked to death in the coop if she wasn’t. This morning, no blood, no scabs i can see and no apparent issues as she has been eating and drinking and fighting restraint normally.
I thought i’d try to reintroduce her to the flock this morning and while no one else cared, Dolly Carton (the bully) literally ran up to her right away and started pecking her vent to the point that she bled. I separated them again but am concerned about re-introduction. Has poor Zoie Eggchanel now become a target and if so who do i rehome?
Is the immediate attack despite no blood being present due to Dolly being unhinged (not in a human sense but in a chicken sense)? Does she remember that it happened before? I love my girls but have means i think to rehome a solitary girl if necessary. I am just not sure which one should go.
The rest of the flock is pretty peaceful except for the occasional squabble which has never turned violent so far.
Has the bullied girl (zoie) been sequestered for too long or not long enough?

 

[oldhenlikesdogs]

Chickens start to vent pick generally for two reasons, one is because of a protein deficiency, the other is because they are bored or crowded. Once it starts it can be hard to stop. They will peck, and cannibalize, so it's important to not return her until you figure out what's going on.

A protein deficiency can be because you are feeding a lower protein ration like a layer, and are also feeding treats. I recommend finding a ration that is 18-20% protein and keep extras to a minimum. Treats should be protein rich if possible, at least until the situation improves.

If you chickens do not have enough room they will start pecking each other in an attempt to get rid of some members. So it's important to provide enough room so they all can get away from each other. It's also good to have places birds can get behind or go under to get away from others if necessary.

I personally would pick up some pin less peepers, and put them on any you see doing the pecking. Than I would check my ration and enlarge my set up if necessary.

Once one starts to peck it may be impossible to stop completely.

 

[thecatumbrella]

Once one starts to peck it may be impossible to stop completely.

Wanted to double-down on this point. It's demoralizing to hear, but it's true. I've gone through it firsthand. If the pin-less peepers don't do the trick, then you're faced with a tough decision.

I have successfully rehomed two feather pickers to a large, free-range flock. I was very transparent about WHY the birds were being rehomed. The combination of having a new flock to integrate with, along with more things to do as a free-range bird, completely removed the behavior.

If they hadn't stopped, they would have become soup.

 

[fldiver97]

I’ve adopted a wheaten Marans years ago that was a relentless bully in her flock. She never caused trouble at my place, quarantine and then having to go into an established flock left her low in the pecking order. She was the first adult hen I introduced by herself. She turned out to be a good flock member (she only had the bad habit of roosting in the rafters and waiting for me to open the big door to the yard…. She’d jump/fly right over my head. It was safer for me to just let them in the run and the open the run door. She was known as Amber, the flying chicken of doom )