If possible.. put out 10/12 FarmHouses. In one full 40EnergyBar.. even if you get a Fangbeast or 2, that consumes 5Energy each.. but you will also be able to spawn a Bear for sure or even 2/3. It's not diffucult to spawn them.. considering the waitingtime of the FarmHouses is only 10min. Just keep on trying till energy runs out.
Remember to be careful of the gem-trap on buying energy that appears when you've finished the energy.