URGENT: How to control sudden feather pecking

[ChickenPerson1234789]

I have 5 pullets that are around 18-20 weeks old. 2 of the lower pecking order birds suddenly began fighting each other with one bird seemingly the cause (as this bird also began aggressively pecking other random birds in the field).

It is sunset where i am at and i have put the troublesome bird in a separate area to sleep/eat immediately once she pulled out one of the other bird’s feathers. The rest four i left in the main coop. Is this the right thing to do? How long should i keep them separated? I always watch them while they are in the field for a few hours a day. Should i let them be and just stop them from pecking each other manually in the morning?

For background, i just expanded (yesterday) the run/coop (was around 30 sq. ft and now is around 60sq ft). When i am outside watching them, they have over 1000 sq ft of running space. Could this be the cause of this?

Any help would be appreciated

 

[RiverOtter]

How bad is the pecking? If no one has a bald spot or any blood, it may just be a bit of scuffling to determine dominance - the pecking order isn't static, and at their age they are beginning to sexually mature, which causes obnoxiousness regardless of species.

 

[aart]

For background, i just expanded (yesterday) the run/coop (was around 30 sq. ft and now is around 60sq ft).

Pics please.