Started 6 mos ago. Chicken had gotten her coive kept an eye on it and it never changed. Now on and off 3 times niw it has went back to a completly normal folir. Like today, this afternoon it was purple. This evening it was only purple on the tront 1/3 and the rest looked healthy. Is it rrost bite that is healingvor is it something else. No one else is affected. I have goid egg production and no other problems mb pooped on this winter and i assumbed she got frost bite, it turned purple.