I'm sorry that you lost him 
He was the one that the girls were picking at his legs right?
He had been previously been living with the until you pulled him to treat his legs right?
Just trying to get up to speed here.
For hens to pick at and attack an almost 1yr old rooster - something was not quite right there, imho.
Are there other cockerels/roosters with these hens?
Hens are not that nice at times, imho, I don't think I would cull productive healthy laying hens - not at this time but I would be hesitant to put another docile rooster with them too. An older mature, larger rooster may fare better.
You mentioned that you lost a good breeding male, did you have specific hens you were going to put him with or just do a backyard mix?

He was the one that the girls were picking at his legs right?
He had been previously been living with the until you pulled him to treat his legs right?
Just trying to get up to speed here.
For hens to pick at and attack an almost 1yr old rooster - something was not quite right there, imho.
Are there other cockerels/roosters with these hens?
Hens are not that nice at times, imho, I don't think I would cull productive healthy laying hens - not at this time but I would be hesitant to put another docile rooster with them too. An older mature, larger rooster may fare better.
You mentioned that you lost a good breeding male, did you have specific hens you were going to put him with or just do a backyard mix?