Sorry about the lost litter. Most of the time, the does only eat stillborn kits, but they do sometimes eat live young.
"Old timers" often recommend giving bacon to a doe a day or two prior to kindling to prevent them from cannibalizing their litters. I think most people assume that this is because the doe lacks protein (since kits are meat, after all!), but it is actually a lack of salt or minerals.
Does she have a salt/mineral block available to her? The only time I have had a doe eat kits while still alive is when they did not have access to salt and minerals.