I live in an area of juniper trees and cheat grass. In an effort to keep any wildfires from spreading from the grass to the trees, people around these parts prune the trees up off the ground and try to keep the grasses cut low around them. I have found that keeping a flock of chickens around has eliminated the need to trim the grass around the trees. In fact when I bought this house there was grass about 2 feet tall all around my wood shed. I mowed the grass one time and our chickens have kept it mowed ever since. I have seen them eat mice, spiders and weeds. They actually don't eat much laying mash as long as they are allowed to free range. They do enjoy some scratch which I am happy to provide in return for the wonderful eggs and the reduced labor.