Another aggressive chicken. Not an adolescent or rooster

[katieroth]

I posted this in an older thread and realized I might not get an answer. So here:
I'm having trouble with an aggressive hen. She's a speckled sussex, over a year old. She was sweet and we got along fine until a few months ago. She started putting her wings down in that attack position. She puffs up her chest and comes after me. I read another thread (or advice place) that said if your roo is doing that, pick him up and walk around with him. That seemed to help actually for about a month, but she's back to it again. She'll run over to me and attack so it's not just when she feels threatened. She also is laying sub-par eggs lately -- thin shells that break. I'm giving them extra calcium etc but she's still not laying well. Also, her personality has changed so much, I wondered if she was one of those chickens that get roo features in a roosterless world. I've checked and there's no sign she's growing spurs and her voice isn't changing.
On top of that, she's also mean to my 3 new pullets. I've taken to putting her in a time-out pen and letting everyone else out. That's only for an hour now and then--maybe I should leave her on her own for a full day, let her battle her way to the top of the flock again.
I'm tired of getting pecked.
Grrrr. Any ideas?

 

[aart]

She may act like cock but not look or sound like one, the funky laying could be part of that tho.

How long have the new birds been there and how old are they?

The timeouts sound like a good idea...keep her in view of the flock all day but maybe let her roost with them at night.

 

[katieroth]

The new birds have been out there since June! One has even started laying eggs. She still chases them away all the time.

 

[Folly's place]

Is she looking boyish? She may have a health issue causing her behavior change. I wouldn't tolerate such difficult behavior! Mary