Yes loss of teeth in older grazing animals is normal . Those brown stains have been there a loooong time. Getting darker, but Not cavities. I keep a sharp eye on him to make sure he doesn’t lose condition. He is probably missing a molar or two also, or maybe ground down from the years. If he gets down to gums, I’ll feed him oatmeal and moistened pellets. Ringo is my Old Man. He’s spoiled. I’ll do all I can for him, but wear and tear is going to happen. It’s not like I can fit him for dentures.Um, is that normal? And should the others have the big brown areas that could be cavities or something?