Can newborn Kittens drink baby formula?

I took in a cat and she's given birth to 2 live kittens, and 3 dead ones :( all 3 looked like they had no bones and one had an open stomach. Anyway, the other 2 are now a dy old, moving meowing and passing waste, but i'm not sure if mama is looking after them, she'll go to them on and off, and if they meow for her, and she'll lay with them, but i've never actually seen her feed them, although they are moving about and don't seem any weaker than any other newborn kitten. The thing is it's 2am here, any shop would be closed until 6am tomorrow. If i stay up and don't see her feed them, can i give them my son's cow and gate formula until then? it's all i have in atm, but like i said, i'll be setting off to get to the shop at 6 for kitten milk. I've rang up out of hours vet, but receptionist wasn't exactly helpful, well she just said 'might as well try it'