My sister in law recently had the same problem with her 2yr old yorkie and her 12wk old puppy she ended up feeding them both Royal Canin puppy, she said her vet told her puppy food is OK for adults so they will both eat that till she is old enough to switch to adult, then she will put them both on adult Royal Canin. So far they've both been eating the food and doing really well. Good luck!
