If they are that tiny they probably still need kitten milk like KMR that you can buy at a pet store and bottle feed them. If you could post a picture it would help to see how big they are. Are their eyes opened yet? They usually open their eyes at around 10-14 days old.

I would keep them away from your older cats until you can make sure they are healthy kittens.

We have some bottle baby experts here who can hopefully give you some great advice.

Best of luck!