While this strategy doesn't really help much for getting an egg. For wyvern milk you could put a ballista turret on a parasaur saddle load a chain bola which does effect wyverns. Then use a fast argy to agro a female wyvern and lead it to the parasaur and down it for milk harvest. Then repeat until you have enough milk to raise your wyvern.

More Wyvern Taming & KO Tips