Breed & Gender of our "rose" and a question

[iamloved22]

We took our 3 roo's as well as a friends in for processing and my daughter fell in love with this bird - the woman said it was part of a "this and that" hatching they did this spring and that she had NO idea if it was male or female, she tried in vain to convince my daughter to pick a bird she knew was a hen to keep us from having to have another bird butchered. She has a very small close to her head comb like my other hen's do and a puff on the top of it's head as well as feathered ankles which leads me to believe it might be a polish mix but I'm really not sure, she appears a few weeks smaller than my 14-16 week old ladies.
I also have a question that hopefully can be addressed here rather than creating another post. We took our 3 roo's in for processing leaving our 3 hen's (all around the 14-16 week old mark) I expected a fight for leadership and pecking order and thought now would be the best time to introduce any new birds, my friend had one roo (which I took in for processing with mine) and one hen - all were originally the same group at purchase and spent a few weeks together as chicks. She gave me her hen and I purchased "rose" in the pictures, the other hen's aren't bothering each other and they seem curious about "rose" but the other hen is being unmercifully picked on, I finally had to separate her when I found the 3 had pecked the tops of her wings bloody, that hen is a bit odd to begin with but is there any suggestions on why they are ganging up on her in particular and if I should just re-home her or is there a chance on a friendship? I've got her separated in the crate but inside the coop and then I put "rose" in with her because I didn't want the other 3 to start picking on her since the other one was unavailable. I can set them up temporarily in a separate space if I need to.

 

[draye]

Rose looks like a pullet. She seems to be a Silkie Cross of some kind.
I usually introduse 3 to four at a time that reduces to being picked on, but sometimes certain ones act crazy and that leads to the others picking on it long with the others that were put in with it.
I've found that I just have to let them fight it out. Sometimes it doen't come out well, but that is nature.

 

[hdowden]

that is a pretty silkie cross pullet. its also a good practice to quarantine any new birds for a month to make sure they are healthy

 

[iamloved22]

Yay! Thanks I really like her she snuggled under my arm when I first got a hold of her. I'm worried they might kill the one pullet especially since she doesn't appear to be quite all there mentally (she tried to hide - put her head into the dirt in the corner of the run bum up in the air like an ostrich!) and once she's gone resort to picking on rose but they didn't seem to be quite as aggressive with her. I'm going to give them a day or two in the crate and then let them fight it out I suppose.