Not difficult I should imagine ,also worth mentioning that there all different, my terrier crosses may fatten on a diet that could starve your fen gremlins ,and mine could shrivel up.and die eating your dogs diet of cous cous and the odd date
Iiiiiii say the reason tripe put weight on dogs is thus ,although it is moderate in fat and protein it is very digestible and breaks down more easily than say beef and the dogs system can utilise more of the calories available even tho they are fewer
5r