9 month pullet/hens: one suddenly attacked mercilessly by head lady

[MirPanda]

I have four hens (still pullets at 9 months?). All mixed breeds: buff orpington, australorp, chantecler (brown) and silver wyandotte. Yesterday our Australorp (#1) started chasing and attacking our orpington (#3) to the point i had to let her inside the house to escape. The attacked lady gets all puffy and cackles strangely, and of course hides her head. Once put in the coop for nighttime, they kept it up until it was roosting time and peace was had. This morning, all over again. Australorp continues to attack the orpington. She's suffered pulled feathers at base of comb and a cut on her comb. I can't leave her locked in the coop, as the others can't get to the nest boxes or food/water. I have a little rabbit cage i could keep her or the australorp in, but then she'd be unable to use the nest boxes. I don't know what to do! they're just chickens, they can be 'chicken'y, but we don't want to see our sweet lap chicken pecked to death, nor do we want to give her away to someone who won't give her lap time. is the australorp jealous? nothing has changed except a new part of hte lawn has been opened up for grazing.
the only thing i can GUESS is that because Belina is the only yellow chicken, she perhaps attracted some attention from a predator and now Soot is trying to keep her away from the others? i heard all sorts of callamity out there yesterday, but figured it was just the chickens' antics. the neighbor dog was barking a lot.

please help!

Miranda in Austin,TX

 

[arch_cpj]

if they keep going after the same area try some no picl liberally on there see if the hen whose a bully gets a mouthful of that and gives it up you have a roo Ive seen where a good roo has a calming effect on the flock and he tends to keep the bullys in check but you need a good roo... of course you could try being the roo try givin that bully a good swat every time she gets picky let her know your the dominant flock member might work...