There are some really good videos on caring for neonate kittens, but a really excellent one is Kitten Lady. See her flier and her video too. She’s got a lot of materials available online, have a look at her channel. It’a delicate balance, and your best chance of success is when you get all those i’s dotted and t’s crossed. She knows how to get that done and can help you keep track of all the aspects.
When you see unweaned kittens, often at the base of a shrub or in thick grass, do not pick them up unless they are immediately threatened, as in you had to chase a dog off them, or they’re soaked or in snow. If the mom is feral, your mere presence may be keeping her from caring for her babies. So give the mom a few hours to return for her kittens, keeping well out of sight and sound. Mom is always best at caring for her kittens, so if she is still trying, let her do it. Kittens under the age of 6 weeks are considered unweaned and should stay with mom if at all possible. Check the age guide to be sure you know how to tell!
When you pick up a neonate kitten, there’s a good chance it will have been through some trauma, even if it’s just having been cold for too long. Warm the kittens well before you try to feed them, and feed them kitten formula. The smallest kittens cannot regulate their temperature, and cannot digest food if not warm enough. Their body temperature should be 99F, so they should feel very warm. If their feet, ears, or bellies seem at all cool, they need to be warmer! Once you’ve got them warmed up and have some kitten milk ready in a bottle, have a look at the neonate kitten guide.
Something that is extremely important is that they eat a goodly amount at at least every other feeding, pee with stimulation several times a day, and eliminate daily (or every other, if they’re not robust kittens). Track the amount they eat by following the level on the bottle as you feed each kitten. See Kitten Lady’s age/weight/feeding/frequency chart. You can keep track of how you are doing with that by weighing them twice a day. You can go to once a day once they start on solid food.
To keep track, make a list of feedings, ml each feeding, if they peed or pood, Morning and evening, also record weight and total amount fed. It’s less important that they hit benchmarks than that they show good daily gain, amounting to about 14g each day. Often you will see their weight flatline or even dip before any other trouble is apparent. Sometimes it’s nothing more than a need to keep them warmer or deworm (you can start that at 10 days, consult a vet for the most gentle product). Sometimes it’s something more serious, so be vigilant for symptoms.
Kittens may be ready to start using litter as soon as three weeks. At this point, they need to have a little more space to move around, in and out of their nest and into a litter box. We recommend keeping them in a larger cardboard box cut about knee high and with the door off their carrier so they can come and go in their box. Add a small litter pan (a small box about 1″ deep) with some sort of litter they will not be hurt by if they sample. Do not use clumping litter of any sort, as it can expand in their bellies and stop all movement.
At four weeks, you can start offering a little pate food with some milk poured on it. It might take them time to figure out how to eat it rather than wear it. So be patient. It often works to put a little on your finger and touch their lips. Once they get used to eating from your finger, lead them to the bowl with your finger and see if they can sample that.
By five weeks, they should have the hang of wet food with some milk poured on it. You can start tailing off the milk and encourage them to eat more pate. Don’t go too fast, let them choose which to eat. Their digestive systems may take some time to adjust, and trying to speed them up can cause upset.
Caring for neonate kittens is tricky and exhausting, and you should seek a partner to work with and give yourself a break between fosters to be sure you do not burn out. It can be described as heart work, meaning the biggest risks and rewards are emotional. Let yourself celebrate successes, grieve losses as you need. Don’t let others tell you how you should feel about it or what you should do.