Stendker Checkerboard Losing Red Markings

[alhaase]

Hello friends. One of my Stendker Checkerboards has begun to lose his distinctive red markings over the past 2-3 weeks. The color change seemed to start at the approximate center of his sides and move outward. He is about 5 years old, and his behavior and appetite are normal. No change in anything, other than the gradual disappearance of the red lines, and the more outboard red markings appear to be shifting toward an orange color as they fade to white. Does anyone have any experience with this to offer advice? Should I be concerned? Any assistance would be greatly appreciated.

[Iminit]

Pictures may help. Are you feeding anything with red enhancer’s??