get the kitty off the hills food, it's one of the most god awful concoctions ever. The vets all push it so don't feel bad that you thought it was good. The company gives great kick backs to encourage vets to use it, sell it, push it etc.
If you kitty is addicted to dry food i'd first mix grain free dry food with the science diet and get him/her off of it first by slowly increasing the grain free food in the mix and lowering the amount of the science diet.
If he/she isn't addicted then i'd just go straight to a quality grain free canned product. Always opt for beef, venison, goat or even rabbit over poultry. Poultry just isn't nearly as nutritionally dense but occasional feeding is fine.
once eating the canned is well established start mixing in the raw with it. Slowly increase the raw and decrease the canned until the cat is eating raw just fine.
I still use grain-free canned in a pinch and with my kittens going to pet homes who may refuse to do raw.
Add probiotics (Primal Defense powder being ideal www.iherb.com
) and CLO (i like to buy the cod liver oil/butter oil mix from www.greenpasture.org
) to the canned to help the body deal with the transitions and healing while it removes all the toxins from the hills food.
I occasionally give my cats a chicken wing to gnaw on to keep gums stimulated and jaws exercised
I also add a pinch of real celtic sea salt or himalayan red mountain salt to their food. I get celtic salt from www.azurestandard.com
and himalayan red salt from www.guardianofeden
. You can opt instead to provide two types of water, in glass bowls, one with the good salt mixed in and the other just plain (both filtered!).
Also raw egg yolks from pastured hens (www.eatwild.com
to find a farmer near you) is an excellent food too!