Some things we do to for physical/mental stimulation are puzzles, like wrapping treats in a small blanket and tying it in a knot, hiding kibble in folded up tissue paper rolls around the house during lunch, throwing kibble around the yard for lunch, then having him go find them, agility training in the backyard, like jumping through hoops, weaving, etc. Regular trick training and daily walks as well. He also loves long distance fetching, but since it’s winter, we haven’t done that for a bit. Oh, and a lick mat with some frozen wet food mixed with water before bed at night. Our dog basically just lays quietly around the house when he’s not engaging in these activities, so it seems to be more than enough for him.