I saw a video on how two people got two perfect 150 argents, one for 200% speed+stamina boosts with a little health, the other had melee and health. The speedy bird would get the egg and the tanky one would kill female wyverns during the growing process for milk. It works, but I myself have not attempted, I will probably test it out on my single player.
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