cows milk is horrid stuff for lot of things... many humans cannot tolerate it, and it can do horrid things to the digestion of most furries.. goats milk on the other hand doesn't seem to be anywhere near as bad..
i've always known about cows milk being bad.. from giving cats the squitts to killing hedgehogs when well meaning folk feed them bread soaked in fullfat cows milk *sigh* but a friend with lactose intolerance, used to be able to drink goats milk.. so.. yus.. its not bad stuff, a bit watery compared to cows..
it can be a bit hit and miss, but generally i work on the principle that anything the adults eat, the babies can, provided its soft enough for them to be able too..
the rat pups, i drip feed from a syringe, they used to lick the mush up..
i've remembered too they used to get readybrek and goats milk - its a breakfast cereal a bit like fine porridge..
if they won't come to the bowl to try it, you can try dunking their nose in it (although try not to get it into the airways!) at which time they should then lick to clean themselves..
you could try adding supplements to the liquid part too.. here.. i would put in a bit of something like critical care, avipro.. maybe some honey.. small bit of bee pollen..
generally though, they should be able to eat what mum does, once its soft enough for them to handle, if they are scrawy now, and you have time for the one on one, then try dropper feeding to start with.. scrawny baby mice i have found don't last that long.. if they won't keep still, then wrap them in a bit of fabric, and just have the head peeking out..
keep an eye on the bellies.. if they start to bloat, the mix is too rich, so cut it down a bit (water it down) they should be able to defecate by now, but if not for any reason, you need to be mum and rub their tummies and "bits" with damp cotton wool to make them pass waste.. not too hard though or they get a bit red with it all..
good luck with them!
Nerys