I'm guessing the best way to know if it is normal or not, is to just pay attention. I have a Cucu Meran pullet who's legs are normally a yellow-ish pink color, but she had recently gotten black on her legs. At first we just thought it was dirt, but it has slowly been taken over her legs. They are not all that raised and those scales are not inflamed, but the others are. Unfortunately she also has a host of other problems from the coop that we have to keep our flock in. However, I am hoping to clear up the mite problem and that will help her get better quicker.