Sudden change in pecking order. Cause?

[TwoCrows]

Yes, if it's not a health issue, it may be an attempt to "over throw the throne". It happens. I saw it happen in my flock once after my flock leader was gone for 5 weeks broody. When she returned the next in line pounced on her something fierce! HOLY CROW...the blood shed was awful! BUT....the flockleader broody won out even though she nearly lost a waddle. LOL It happens.

 

[oldhenlikesdogs]

@oldhenlikesdogs
 interesting about the young rising up to overthrow the old. Just like real life... This is the first hen I've had that has lived past the age of three, so new territory for me. But the bantam seems pretty spry other than all the white on her head. Maybe she's just getting tired, though. 

It could be the bigger birds finally realized they were bigger than the bantam. Flock dynamics change. Once a chicken gets frightened they can often overreact. I see it in the fall during the molt.

If a hen gets picked on while she's not quite feeling well like during a molt, they can become unreasonably fearful and it can take some time for them to calm down from it. It doesn't help when a birds is acting that way, that the rest of the birds feed on it and it becomes worse.

Spring is always a dramatic time in a flock of chickens because of the surging hormones, and the desire for each bird to be in the best situation so her offspring survives. Most don't have offspring, but they still follow instincts.