Board Thread:Questions and Answers/@comment-4627764-20151213210306/@comment-27408508-20151218085137

Actually I think nor order, nor level nor happiness have anything to do with breeding chance, but I can't be sure about it. Just read it somewhere in the wiki.

Anyway, my Thumpies and Congle are both level 15 with 100% happiness each, and so far I've got 4 succesful attempts (I always try to wait for 10 friend-lit torches before activating them). No upgrades to breeding or hatching structures, and I've only got my basic ones.

Since they are automatically listed in the order Thumpies, Congle when I open the breeding structure, I always unintentionally put them in that order, which is the opposite of the one which got you your first success.

My guess is really anything does not matter, just torches and luck. I hope you get many more.