When stealing eggs if your on a single player world playing with friends you can use the 300 metre host border to get eggs. You get the host to die near the egg you want then you can pick up the egg and get the host to spawn at a bed and you'll teleport to them with the egg.
To know how much time need to the next feeding just do the next. Look the Food number# then that number multiply x 10, then divide /3600 and the result will be the number of hours until the next time need to be fed. F.E the food number is 1850.5 1859.5x10=18595 /3600 = 5.1 hours
A fire wyvern is one of the best you can have because they are resistant to fire damage so alpha wyverns are much easier to kill same with all the wyverns they can't hurt each if they are the same element but the bite attack still works on all wyverns keep this in mind