Chicken Tractor. AUTHORS: Andy Lee and Pat Foreman. The permaculture guide to happy hens and healthy soil. A chicken tractor is a bottomless pen that fits over your garden beds. Just set it where ever you need some more fertility in your garden. The chickens scratch and peck, clean your beds and eat pest bugs and weed seeds. This system is for 8-10 birds per pen and will work for egg layers or meat birds. A small scale system for homesteader-types. If you want to raise birds commercially see Herman Beck-Chenoweth's Free-Range Poultry Production and Marketing or Joel Salatin's Pastured Poultry Profits. Soft Cover, 318 pages, 7" x 9". To order by phone call toll-free: 866-596-9982.