slime-rancher
The 0.4.0 update introduced locked treasure pods found all over the map, which can be opened once you have the required upgrade, but they're not purchasable right away.
So far I've found three different kinds of treasure pod, but I've only been able to buy the lowest level of Treasure Cracker.
What causes the Treasure Crackers to become available for purchase?
The game developer Nick Popovich has confirmed in a Tweet that there are requirements other than time.
Rad Slimes can be found in The Indigo Quarry.
They were added to the game on April 13, 2016 with the aptly named Indigo Quarry Update (v0.3.0)*.
Rad Slimes are Slimes found exclusively in The Indigo Quarry. Unlike other Harmful Slimes they do not deal damage directly, but when exposed to their aura for long enough Beatrix will start taking constant damage as long as she remains within the aura.
Excerpt and photo from Slime Rancher Wikia
*Rad Slimes were obtainable in earlier versions of the game, but were unobtainable for versions between v0.2.0 and v0.3.0.
I don't think there is a way to really breed Roostros more effectively. There isn't a 100% chance that a Roostro will make another Roostro in it's lifetime. I'd recommend 2-3 roostros in a coop with 3-4 more hens of your choice. You should definitely trade with Mochi Miles so she invites you to her Ranch. You can then get a better coop and hold double the amount of hens if you take up the deal she offers you on her ranch.
Best Answer
Seems to be based entirely on Extractor Cycles (get items from drill/pump/apiary buildings) now that I've played more.
Mk1 (Green) Treasure Cracker:
Mk2 (Blue) Treasure Cracker:
Mk3 (black) Treasure Cracker:
Slime Rancher Wiki found the exact(?) numbers.
You usually have to sleep to get the unlock to pop, but one time I did not--might check every X hours or Y time of day instead of whether you slept.