hen pecking other hens hineys till they bleed

[merkjonson]

I introduced new hens to my flock, i waited a week to put them together i introduced them now my original hens are picking on them around there vent till it bleeds they make anti pic is that a good move or will this pass

 

[GardenState38]

I'm also interested in hearing answers to this.
From what I read, feather-picking can become a habit with hens, so it's best to try to "nip it in the bud", if you can. One hen can also "teach" others to pick.
I just started to have a problem with my Wyandotte, lately, who is picking my Cuckoo Maran's vent area (just the one) and has picked the beard off of my faverolles. They were all raised together from chicks.

I sprayed a product called "Hot Pick" on the Maran's vent area and it seems to help at first, but requires re-application. It contains soap and "spices" (probably cayenne). I'm not going to use it on the Faverolles, though, because I don't think it would be wise to use it in her eye area. Also, since her beard is nearly all gone now, interest has transferred from her to the Marans.

I've also ordered "pinless peepers" to try on the culprit, but they are unfortunately on backorder. In case you don't know what they are, they are a plastic "blinder" that snaps onto the beak, and prevents the bird from seeing directly in front, thereby making them incapable of focusing and pecking. I'm hoping that some time with these will re-focus her interests on more normal pursuits...

Possible causes of feather picking, which may also need to be addressed, are nutritional (protein) deficiency, overcrowding and boredom.