ex- battery hens

Hi, Ive kept chickens now for nearly a year without any serious problems. At present my hens are still laying and are very healthy. I chose Warrens as they are good layers and very placid,but also prefered by battery farms.
I have just aquired about a quarter of an acre of overgrown land to the rear of my property,ideal for hens. As we have a battery farm locally I thought of re-homeing some of these once the land was cleared. Are their any serious issues to consider before choosing ex-battery hens....thanks Aden..

On the bright side they do eat less when not laying.