asked how the snapper is being kept? at 10-15 inches in shell length it would require a pretty decent tank ( what size tank is it in?. whats the temp of the water you are keeping it in? is there a basking spot ( yes i know snappers don't always bask, but maybe providing one that isn't eating might cheer it up) basking spot if you give him one should be like 90-100?.......are you keeping him in good clean water? i have read that snappers will eat veggies. my friends common snapper ( i forget if you said it was a common, what kind is it? where are you from?) would eat collard greens, turnip greens, and mustard greens. water plants might be good too. not only will he be able to hide amongst them, but he can snack on them. anachris is a good aquatic edible plant. non eof my turtels have ever hibernated. my ally snapper is kept with out a basking spot and water is 78 degrees. just eats and eats. even wild caught older turtles never hibernated indoors for me. not eating does not seem right for a snapper. i have read of reports of them being seen moving around under the ice. could be that there is something wrong with him. perhaps he is sick. the fact that he lets you scratch him on the head and he never snaps also don't seem right. especially for an older wild caught animal. you say he gets along with your cats and dogs????? your turtle isn't eating. hasn't for a yr. i would set him up really good, and not take him out of the tank tell he does start eating. perhaps all the contact with you and other animals and being taken out of the tank and picked up and being moved around isn't helping him adjust to his new captive environment ( yes i know thats a run on and i know its been in captivity for a yr). i think the most important thing is to tell us how you got the turtle set up.
as far as foods, worms, fish, crayfish, i feed mine rodents ( thawed out ones), trout chow, jumbo dried shrimp ( was a food at the pet store for fish), reptomin. ....i don't know how healthy hotdogs are for the turtle. i would definately get him on something else . sorry if i missed an earlier post about how he was set up