I have noticed this before and again today. Both of my Danish leghorns have purple spots in their comb, it's as if one side of it is turning blue. They're acting normal, eating well, laying eggs. I'm going to attach some photos. Unfortunately, I am in a boot, and can't chase them right now ! I tried to get as close as possible to take photos. None of my other chickens are affected, And they are all different breeds. My leg horn's have a very big floppy cones. It has been getting very hot here, and today it was 101. When I went out there they had knocked their water over, so I wonder if this could be dehydration?