I am currently mama to two kittens that were found at about 10 days old, eyes still closed. There were 6 of them, born to a feral mama who left them, found drowning in a windowwell during a nasty storm (well, 7 but one was already dead). I have been caring for them since they were 4 wks old. They have been bottle fed by a friend and myself and all are thriving.
My suggestion is to make your own formula, as the formula that you buy for kittens in a can gives them horrid diarrhea.
Here is the recipe we used, we got it from our vet.
You can get little bottles and tiny nipples from petsmart, or order them online in bulk. The starter set its about $5 and you get one bottle and 3 or 4 different nipples. Once they start teething, they will really bite the nipples up.
Cut a decent size hole in the nipple, and slowly squeeze as they drink.
2 12 oz cans evaporated whole milk (or is it 14oz? I can't remember,20either one is fine)
2 envelopes unflavored gelatin (like Knox, I buy Kroger brand)
2 egg yolks
2 tbsp full fat mayo
2 tbsp full fat yogurt
2 tbsp molasses or corn syrup or honey
You microwave 3 cups of water till it boils. Add the gelatin and sti r till dissolved. Slowly add the egg yolks while whisking. Add remaining ingredients, whisk, and refrigerate.
It firms up like jello in the frig, Just use a small syringe to suck it up and squirt it into the bottles, then microwave them, or scoop a little into a small bowl and use a funnel to put into the bottle.
Let me know if you have any other questions. When they are this little, they will need to eat as much as they will take, every 2 to 3 hours around the clock. We had one that needed to be tube fed for awhile, because he couldn't suck.
Also, get natural, no clump litter, so if they eat it, they don't choke. Also, just a couple minutes after they eat, hold them over the litter and gently stroke their belly so they go to the bathroom there.
We also took an old fleece blanket and cut into smaller blankets for them to snuggle into.
Just a couple pictures to show you them. They are 10 wks old now. These pictures are when they were about 4 wks old.
This is Marvin. The only long hair of the litter:
And this is Kip. We kept two of the boys:
You are wanting to do a wonderful thing mama, but it is a LOT of work.