My tiny RIR is becoming a terror - how do I stop the behavior?

I have six hens, three BO and three RIR. Sweet Pea, my smallest RIR (I call her the runt) has started terrorizing the largest RIR (Tinkerbell because she loves to fly), who is considerably larger. This started about two weeks ago and is getting worse every day. Sweet Pea won't let Tink near treats, she starts chasing Tink for no reason that I can see. Today she chased Tink all the way across the run, caught her, jumped on her back and started pecking at her head - I had to break them up. She won't let Tink onto the roost. If she is able to get onto the roost Sweet Pea manages to get next to her and pushes her off. I have to catch Tink and put her in the coop at night, she doesn't want to go in. I think Tink slept on the sand on the poop board last night. I am afraid Tink is going to be hurt. Recently I've noticed the other hens pecking at Tink and afraid they are learning from Sweet Pea. Their coop and run are more than enough space for six hens so they aren't overcrowded. I have all kinds of "toys" , swings, perches,swinging cabbage, CDs etc. to keep them entertained so don't think they are bored. It certainly isn't heat, it is freezing. I've read on other strings to isolate the offender for a week in a place where she isn't with the others. My problem is that I don't have a place to keep her isolated. I am wondering if it will it do any good to put her in a large wire dog crate inside the coop and keep her there day and night? She wouldn't be able to intermingle with the others but she would be in full view. I hope someone can give me advice. I don't want to rehome Sweet Pea, she is a cutie but this can't go on. Well, I'm off now to try to put everybody to bed for the night and stay there until, hopefully, everyone is settled down. Thank you!

I would separate sweet pea for about a week and a few days or so just so she is not a part of the flock any more and will be reintroduced to the flock and you need to do this before the others learning from sweet pea start attacking her two

Oops sorry I didn't see that you said about that not being able to isolate her could you put her in your dog crate as mentioned and set it in the coop but somehow don't let her see them and them see her

Yes, I sure can. I can put the crate in a corner with a board in front blocking her off. I hope this works. Thanks

No problem I hope it puts that little terrorizer back in her spot in line

Dog crate thing might work......but......
Tell us more about your coop and flock.

How big is the coop (feet by feet)?......a pic would be good too.
Do you have a run? ...again size/pics.
Are all the birds the same age and grew up together?
Any changes in coop, feed, or population lately?


ETA: I see on another thread of yours that you have a sick bird....is Sweet Pea or Tinkerbell the sick bird?

Sorry - just found your reply. No, neither of these hens are my sick one. She is ever so slowly getting better.

She can't see them at all and they can't see her right glad she is getting better

I picked the chicks up from Cackle Hatchery in Lebanon, MO when they were 24 hrs old (June 25, 2014) so they are the same age and were raised together. There have been no changes to the environment since July when I had to find a new home for my roo. Their feed was changed recently from layer to chick starter but this behavior had already started, a little pecking but nothing serious. The brutal attacks just started. Because I have the recovering hen, I was advised to use starter feed for the additional protein - she is weak from being ill for so long (they have oyster shell at all times).

The coop is 8' X 8'. The run is 24' X 40'. Half of the run is under roof (24' X 20') the other half is covered in 1/2" carpenters mesh. At this time I have the run wrapped in plastic all around plus plastic dividing the covered and uncovered part but they are able to go from area to area if they want. Mostly they stay in the covered part where it is dry.

The coop is a bit full right now because I had to isolate the other RIR - same thing, running Tink down, jumping on her back and attacking her head - so there are two large dog crates in there. Both crates are blocked off so they cannot see each other nor can the rest of the flock see them. The three BO don't bother Tink but she is so intimidated that all they have to do is look at her or move and she takes off. Is there something I can do to help her gain her confidence back or just give her time?

So far one positive thing has happened. I have had to catch Tink to put her in the coop for the night because she didn't want to go in. Last night she went in with the others - yeah.

I will send pictures this evening if I get home before dark - otherwise tomorrow.

Thank you.

I am on BYC on my Android phone. The message is typed and pictures attached but I cannot see anyplace to press "send" Does anyone know where the send button is located?