Wyverns only eat Wyvern milk until they are adults. Their food value is high for a hatchling, and drains very slowly. You only need to feed them once the food bar drains, which is once every few hours. They can hatch and wonder around for hours before starving. Female Wyverns need to be knocked out to get 5 milk from their inventory. Milk does not refresh. And if it wakes up again and gets knocked back out, milk vanishes out of the inventory forever even if re-tranked. Kill the female once you get the milk. If you need a lot of milk, summon an alpha and eat it with a giga. They drop 50 milk. Milk spoils in 45 min in inventory, And 3-4 hours in a preserving bin.
Eggs hatch a dragon the same level as the parents. Higher stats mean easier to raise, and better quality dragons, more food bar to burn before it starves, and less likely to be killed by stuff in the Ark as an adult.
Eat eggs you don’t want. Do not drop them. Dropped eggs do not re-spawn. You’ll see empty nests.