Hi Sally,
Sorry for the delay!
Check their mouths to be sure they don't have any oral lesions which may indicate calicivirus infection that can make them painful and not want to suckle.
You may need to tube feed them to insure that they stay hydrated and nourished. You would need instructions from your vet about this, and I'm including some good links, below, for hand feeding abandoned kittens.
KMR is a good supplement, but it should not be fed hot...just lukewarm, at best. Test it on your wrist and make sure it's not too hot for them before feeding. Also, make sure the opening in the nipple is big enough but not too big. Try dropper feeding if they won't take the bottle. Go very slowly, from the side of the mouth where there's an opening between the upper and lower gums, or try from the front, like with the nipple, just go slowly and encourage swallowing by gently rubbing the throat. Keep them in the same position as you would for bottle feeding, on their belly, not on the back!
Also, make sure you're stimulating these kittens in the rectal/genital area to be sure they are urinating/defecating and have not become constipated!! That could be another cause for them to lose interest in suckling.
They need to be kept WARM at all times! Kittens can't regulate their own body temp., and cold kittens can't metabolize food properly.
A vet check to assess for external (fleas/mites) and internal (intestinal worms, protozoan) parasites and FeLV (Feline Leukemia Virus) would be a good idea, ASAP!
http://www.petcaretips.net/orphaned_kitten_care.html http://maxshouse.com/kitten_care.htm http://www.thepetcenter.com/gen/kit.html http://www.cathelp-online.com/health/kitten1.php These all contain good information; most of it is repeated, but they're all still good!
Good luck! Let me know how they're doing.
Cher
If my answer is helpful please click ACCEPT. Click reply for more info. Please talk to me before considering leaving neg. feedback; my only goal is to provide helpful answers. Thanks!