Transitioning Kitty to raw, do I need supplements?

It has been for-ev-er since I've been on here! Life has really kept me busy lol But we have a 6 month old kitten that we're transitioning to raw. I've been starting with chicken wings, heart, and beef liver. I found a link which stated I should be adding all these supplements to her diet, which scared me a bit. I thought I could just do a plain raw diet like I feed my chi, Venus. Are cats really that different?