Leghorns are known to be very flighty and easily agitated. Some more than others. If she's still laying and blood isn't being drawn then she may just be acting really wild at any little thing. The other red chicken may not like that behavior. But I agree with the above that removing the red chicken to reset the pecking order may help. My grandfather and a few other farmers around used to raise hundreds of leghorns each and I've seen them literally flip out over things that other chicken breeds wouldn't even react to. Not trying to disparage the breed, they have a very good feed conversion ratio and lay a lot of eggs and some are fairly normal.
Thanks for this info! My Leghorn pullet was getting bullied harshly over a couple of months ago, but I did and do wonder if she was making a huge fuss more than anything, and while that is not a reason to be bullied, I do wonder if it aggravated the bully.
My Leghorn would make an awful "Buh-
GAAAHHH-bu-
GAAAHHH! bup-bup...Buh-
GAAAHHH-bu-
GAAAHHH! bup-bup...Buh-
GAAAHHH-bu-
GAAAHHH! bup-bup..." , sound, constantly, after something startled her. I wondered if because she was already on tenterhooks from being stalked down and stood on by the bully, but even if I just stood there ten metres away from her, she'd make this noise. It was very unsettling...
I tried isolating the bully but I had her out of sight of the leghorn, so it was not effective. It did though allow my leghorn some peace to recover for a bit. However I later caught the bully in the act and disciplined her on the spot (she ran off sulking!), and that fixed the problem. Both chooks now forage and sit together nicely.
In future though I will build a "Bully Box" isolation area where she and the victim can see each other, to make the process effective.