From Shepherd's Library

Understanding Energy

There are two types of energy - max energy and available energy. Each animal has a max energy level that they can recharge to, for Gen0 sheep the max energy is 1,000. The available energy increases and decreases depending on your in-game action.

Available Energy Max Energy
Gather resources to use or trade for wool. Burn a sheep for chops (1 chop per max energy) to sell, burn for wolf breeding, or trade for resources or wool.
Breed to create Gen2 sheep which are worth chops and collect more resources. Burn a wolf for pelts to sell, upgrade structures, or trade with other players.
Convert to Peak Credits (1 credit per max energy) to sell or use for Peak Games.

Recharging Energy

Energy can be recharged by Bathing your animals or drinking Jugs. The recharge length, jug energy amount, and cost depend the level of the structure and the cost that the owner sets. Bathing in your own structures is a great way to lower your costs in the game.

For more on Jugs and Bathing, check out the Structures page.