Two of my Plymouth rocks and one buff orp squat when I stoop to pet them. One had to have her foot looked at because something injured it and aft picking her up to do that, she squats for me to pet her if I'm near. I take it as a submissive behavior.
That helps! Dixie is doing that, but only when I go to pet her.. She is head hen, even with our rooster, Carl around. He's pretty submissive for a rooster