Ok - thanks all. I've got J***'s, Stalosan F, Vanodine V18 and can buy any other options. The soil I've got is mud, stones and underneath that, hardcore, so rotovating is out of the question. I want to disinfect the soil to get rid of Avian Anovirus which caused Egg Drop Syndrome, so I assume I need something fairly strong, and when it's disinfected I can hopefully put on some compost/soil and grass seed before any more chickens go back. Which would be the best disinfectant to use?