Pecking Order.

[Kaceyram11]

I have two older hens, speckled Sussex and Barred Rock. Also one white crested polish. She’s about 2. Older ones nearly 6. Had 5 but lost 2 to a skunk last august. The sussex really beats up on the polish. She’s definitely at the bottom. The barred rock tolerates the polish. Lately the polish wants to roost and the sussex never lets her. This week I noticed the polish is roosting despite getting beat up over it. She’s standing her ground….I witnessed it tonight. It was sad but the polish is still on the roost. Should I intervene. The older ones don’t pluck her head feathers. Never an injury but the sussex is relentless. Is this normal? I hate it. I’m adding 4 more chicks in a few weeks hoping he polish can pair up. She’s lonely.

 

[Lacy Duckwing]

It takes an estimated two (2) weeks for new chickens to adjust to a new pecking order. If this isn't a new pecking order, then it could be a bullying thing. You might want to provide a bigger run with places for the Polish to hide or escape the SS. In the long run, I don't suggest a top hat breed with a flock that has none. They might get confused, and attack her more because they don't realize she's another hen. She might be too different.

Maybe you should separate the Polish until the chicks are old enough? Then get the Polish and the chicks used to each other so they can move in together. But if this is a bullying issue, you might want to rehome the SS, jail her for a month, or give her a Pinless Peeper. Jailing the SS for a month would be my top suggestion if she's a bully.

 

[aart]

I’m adding 4 more chicks in a few weeks hoping he polish can pair up.

Likely she will be the most aggressive to the new birds, pretty common for the low bird.

 

[DobieLover]

If this isn't a new pecking order, then it could be a bullying thing.

Or it could just be a personality conflict and she will NEVER like her. It happens with people too...
And yes, as @aart mentioned, the Polish will very likely beat up on the newcomers. It's a common behavior for the lowest ranking flock member to beat down the new comers as a means of keeping as many of them below her in the pecking order as they transition into the flock.