Trap a live female wyvren in a stone behemoth gate trap and make it pass out with sleep darts and then get into it's inventory and take the milk, get the milk to preservation bin quickly, build 4 foundation room with as many stone fire places and close it in, baby hatches give it 1 milk at a time keeping extra in pres bin, sorry so many trolls out there hope this helps and if it sounds crazy YouTube has great videos