My recommendation:
Buy or trade for habitations and watering holes. You only need one for each enclosure type, if you're stingy: set up one breeding pen with those two in it, and then move breeding pairs in.
Upgrade your breeding station for diamonds if you can; it helps and it's one of the better ways to spend diamonds, if you have them.
You do not need to breed at all. You can completely skip this entire aspect of the game and be just fine. It's the best way to get herds of diamond animals. It's not going to end up significantly cheaper to breed money animals than to just buy them, although you'll get more XP if you breed.
Some guidelines:
- Most breeding equipment (habitations and water holes) you can buy or trade for. (I think the sole exception is the water habitation - that one doesn't come in cards)
- Having a habitation and water hole increases your chances by 15%, which is a lot.
- Upgrading your breeding station gives you another 15%.
- With no habitation, water hole or breeding upgrades, your chances are terrible and you might as well not bother.
- Diamond animals are very cheap to breed.
- Cash animals tend to cost between 1/3 and 1/4 of their purchase price to breed
- Your chances will often end up being around 1 in 4 without breeding station upgrades, or 1 in 3 with them.
- So, compare the price for a new animal to the price for breeding.
For example:
An alpaca costs $215,000.
Breeding: $50,200 x 3 attempts = 150,600
x 4 attempts = 200,800
Breeding chance:
- 7% without bonuses: never worth it
- 22% with habitation and water hole (~1 in 4): close, but an okay gamble
- 37% with breeding station upgrades (~1 in 3): totally worth it