Do hens attack sick hens

[Danielle and her chicks]

Hi there my name is Danielle and I’ve had a backyard flock for 1.5 years now.
8 of which have been together since getting chickens , 5 large breed ( maran, barred rock, Easter egger and 2 RIR) and 3 silkies.

Lately ( last 2 weeks) the barred rock has gotten sick and is isolated.

The chickens have always got along and have an acre to free range and have a large coop.

Today the EE,RIR and marran held down one of the silkies and attacked her as a group. My husband made the silkie safe and they went about their day.
When I got home and went to close the coop for the night the silkie was dead and the feathers plucked out.

Why would they all start to attack her suddenly , they never had a mean side before especially the marran.

Any advice would be great, thank you. I’m one sad chicken momma tonight. I feel so bad for what my sweet silkie went through tonight from her “family”

 

[sekeyslaks]

That's horrible,so sad this happened to you! Yes chickens usually attack or more often drive away sick or different looking chickens(like Silkies to your "normal" hens) Always be wary of their health if a flock starts acting more aggressive to each other. Fall is molting time as well and most chickens are very cranky as they renew their feathers for the year.

EDIT: I recommend you separate your other Silkies if you can because with 2 left the other's will notice the difference in them too and attack.

 

[sourland]

sorry for the circumstances. The removal of the barred rock from the flock may have upset the pecking order and increased aggression in the flock. I'd keep a close eye on things to forestall any more casualties.

 

[Danielle and her chicks]

Thank you for your replies I will keep all of these things in mind. Happy clucking

 

[chickens really]

Proper nutrition for certain breeds is a must because behaviour will change if feed isn't 100% balanced.