@Ashley M Do you have some Karo Syrup or liquid honey? You can smear a tiny bit on the kittens gums or lips. It will give his energy a boost, then try offering mom's nipple again.
I can definitely see that you have a runt in your picture. He clearly needs feeding by hand for awhile.
We need to do something quick, so let me know what's going on. If you have a dropper, I can tell you how to make a little homemade formula to use until you get the real kitten formula.
Yes. Like a teaspoon of sugar in a quarter cup of water. Stir well. Rinse out the medicine dropper to get any medicine off it. Hold the kitten on its tummy with its head up. Never on its back. Couple of drops. Let it swallow and breathe. Then a couple more. Then put the kitten back to mom and tell me if it is sucking.
And then I'll help you make something better for the kitten to drink when you're ready, ok?
Yes a heating pad or hot water bottle wrapped in a towel. If you don't have those put some raw rice in a sock and microwave for 5 minutes and wrap that in a towel.
Tummy down, head up like the way the kittens feed at mom. Put one or two drops in a cheek. Wait for the kitten to swallow and breath, then repeat. The formula needs to be warm as well. the kitten cannot digest cold food.
It is time consuming and takes a little practice. Don't get discouraged. Just keep trying.
After he is done eating, start w/.5 ml and if he eats that try another. He will need to be burped. Hold him belly down in your left palm and gently tap his back w/your right hand.
then you'll need to help him go to the bathroom. with a warm, slighly damp cotton ball gently tap his bottom near his tail. and wipe. You can also put him by him mom and see if she'll clean him and help him eliminate.
Tummy down, head up. Two drops in the side of the mouth. Let her swallow and breathe and go again. See if you can get a full dropper's worth in her. If she takes it well, give her more.
Then, hold her on your shoulder and pat her on the back to burp her.
Then rub her tummy to help her digest. Rub her bottom with a warm damp cloth to help her pee and poop.
Then try to feed her more in about a half hour to an hour.