Molting aggression?

[Cubzwin1908]

I have an 8 year old hen that rules the roost around here. She is my only older girl, the rest are 1 year olds. Several months ago a stray was found in the neighborhood and the kids who found it assumed it was mine and brought it to me. Sweetest, tamest girl I've ever had. After quarantining, we took a good long time introducing her and other than the one that is right above her in the pecking order all has gone well. (There is one even lower than her) I have been especially proud that Blanche, the top old girl has been so accepting of her. Things have been fine for months now.

Blanche has been molting....and usually it's a hard fast one with her....I'll go out and wondered if she exploded. This year it has been drawn out and slow and she's still looking a fright. The last couple of days she has taken to attacking the newest stray - following her and jumping on her back while grabbing back feathers.

Could the molt be causing aggression? She isn't mean to anyone but the newest member - even though they have been almost buddies for a while now, not even the one that is lowest in the order.

I have the attitudinal one separated from the rest for now but not sure how to proceed.....any suggestions?