Good Morning Marissa,
Concats and thanks for rescuing this wee kittah.
He should be seen by vet to determine his age, weight and get dewormed.
Feeding
You can give him a little bit of wet food and see if he eats it. If he does eat it, then you can begin changing his diet. You can mix some formula with the wet food for the first couple of days and then ween him off formula. Make sure you feed him kitten food because it has the extra protein and stuff he needs to grow up healthy. You will need to feed him as much as wants to eat.
It’s important to keep him warm as kittahs can’t regulate body temperature (for the first 3-4 weeks). You can buy a cat bed but a box with a warm, fluffy blanket will be just as appealing.
When you stimulate him, put him over the litter tray so it goes into the tray. Then put your wee guy in the tray with NON-CLUMPING litter (Kittahs are known to eat clumping litter). Do this periodically throughout the day and he should figure it out quickly. I wouldn’t use a tray that’s too low because once he goes on his own, he will fling litter everywhere.
Here is the guidelines for Bene-BAC
Newborns- 1/2 gram at birth; 1/2 g on day 3, 5, and 7 and at weaning. Hand fed orphans increase to 1 g on days 7, 14 and introduction to solid food.
Maintenance – 1 g for every 10 lbs. body weight
It’s great that he’s active because that means he’s feeling better and getting stronger. He will play and romp around and then *klunk* fall asleep. He can sleep for up to 16-18 hours a day but he does have energy to burn off. Within the next month, you should invest in a cat scratching post to begin good behavior. Good luck and always check back if you have more concerns and do give us an update on your boy. BTW-What’s his name?