The best thing that me and my friend does is make a good trap, a lot of traps work so go look up some wyvren traps and build them. The second thing is you want a Argy with at least 175% speed, I have mine up to 200% so it works wonders. Once you have trapped it you want to stand a ways back so they can't activate a trap, then have you and a tribe member shoot with tranq arrows ( surprisingly it doesn't take a whole lot to knock out ). Once you have knocked it out have a friend or you to keep shooting it with tranqs so it does not wake up, grab the milk and fly back to base, you can eaither kill or leave the wyvren alone it's up to you.
I got a level 150 lightning egg and I was so excited to hatch the egg...that when I went to put the egg down I accidentally ate it instead. :( ps4 users: R2 ISN'T GONNA DROP THE EGG YOU'RE GONNA EAT IT LIKE ANY OTHER EGG. REMEMBER THIS. LOGIC BEFORE EXCITMENT.