hi there! i noticed my 3 month old linoheadXnz bun's skin on his ears are of a different color it looks half dark brown and half pink. its pink on from the base and goes dark brown halfway to the tips.. is this normal? should i be concerned? its even and smooth like the rest of his ears, its just a different color..he's neither picking/scratching (aside from his normal grooming sessions) nor does it have flakes/scabs/wounds on it. its been like this since i got him at 2 months and he's been happily eating and lounging and pooping. i guess i just want to know if this should be looked at or should i be concerned about it? it looks like its the actual color of the skin on his ears though, do rabbits get birthmarks? is that what it is?