Breeding is now out for these. Also the best way to get eggs is a Managarmr and mushroom brews. Just bounce around down there from nest to nest. Make sure to leave render distance to reset the egg spawn and also to lose the aggro on the drakes losing their mind after you steal the egg
They lose 1 point of food every 15 seconds, so to time how long until they start starving, multiply their current amount of food by 15 and then divide by 60 twice. This will give you the number of hours left untill the food stat reaches 0.
Obtaining this creature will require you to enter the tek trench where puprle liquid and the nests of these creatures lay past the bioluminescent chamber, there you must steal an egg and raise in a cold environment feeding it nameless venom you can get by killing nameless
It's quite easy if you know how to do it. First, get a decent megalosaurus or spino (I used a wild tamed meg with 382% damage), you can easily get to the trench from the element falls. Then, pick ONE egg that you are targeting. Kill the rock drakes around it. Make Zipline paths to that one nest and grab the egg. Zipline back to your mount and run. If a rock drake attacks you before you are on the zipline, use an apprentice or higher shotgun to kill it. Good luck survivor! Enjoy your rock drake!