I looked around , I hope this is in the right section. I let my chickens free range for 3 or more hours a day. Then I clean up the poop from the ground. Usually by sweeping it into a dust pan and digging a whole in the ground. Some of the poop is more brown and really sticks to the ground , even with high a pressure hose. Any suggestions of how to remove the 'brown spots' on my patio.? Thanks. If this keeps up, before long my whole patio will be all stained spots. Ewww!