Scrub the house with a disinfectant. You should be able to get this at your local feed store. You may also use a hot water and lye solution. Use one pound of lye to 10 gallons of hot water. Let the house dry for a couple of days before using it.
Keeps feed free of mice and rats.
Use a metal trash can with a tight fitting lid or some thing like this. Check the chicken house thoroughly for holes in the screens or chicken wire to prevent animals from getting in. Cannibalism and feather picking is some times caused by overcrowding, nutrietn deficiencies, too much light etc. Watch out for these things. Some times the sight of blood will also cause picking.