One concept of permaculture is to maximize the natural symbiosis of living and growing things so as to make use of what nature has already provided to get the job done.
A chicken tractor is a portable cage that lets your chickens help you in 3 ways:
1. They weed your grass, producing eggs high in Omega 3
2. They fertilize your soil
3. They eat insects
Put 'em in there and they get to work. After a while, roll it to the next location.
Avoid fertilizers, pesticides and lawn mowers all at once!