How do i know if a doe is feeding her kits?

without touching them or poking at them how do i know if the kits are being fed? the doe has already eaten 2 now,and 1 has died from wriggling too far from the nest and getting cold, but 3 or 4 are left and are wriggling around. they are almost 2 days old. but im wondering if they are being fed as i keep finding them a long way from the nest, could it be they arent getting fed? or maybe doe is seperating them off, or they were being fed and still attatched when she hopped out to feed herself? so many possibilities. would they live for long if they werent being fed?