Ask your local battery farm for their older hens. They usually replace their stocks after hens have had their first year of laying.

You can usually expect to buy these older hens for around $1.50-$3.00. They will look in poor condition, but if you feed them an unlimited supply of laying pellets, provide them with plenty of moving space, sunlight and fresh air, they will be laying for you and looking healthy after a couple of months of recuperation.