Does it have to be plain yogurt? We only have Trader Joe’s Greek Honey yogurt in the house at all times.
No, flavored yogurt is fine. It’s only a few times a week, and honey is good. Dogs benefit from a bit of sweet anyway. I’d give Zeus Chobani blueberry, raspberry or vanilla. I’d put it in a dollop on top of his food and he would carefully lick it all up before he would begin the rest of the meal.