of the same brand kibble should I still do a slow transition? I've been thinking of changing from Wellness Core to Wellness reduced fat. And, will a reduced fat kibble be ok to give to my other dog who is thin to normal weight?
I'd do a slightly slow transition but not much since the ingredients difference between the two formulas is not that much. You can give your thin/normal dog the reduced fat, but you might want to feed more of it or better yet scramble up an egg so he/she can get an extra calorie boost if he/she starts loosing weight at all.