Increase your bonuses with your Stable

When you have your own stallion, you get a chance to increase your bonuses.

When your stable becomes ready make sure you have your mares and other stallions at least 33% or more (till 99%).

All you have to do is when the stable is ready after you harvest it, look inside and take one of the mares or stallion out.

Replace it with a horse (mares or stallion) that is at least 33%, you may keep doing this until you are out of mares.

Each time you will harvest new foals, farmhands, arborists and/or coins.