Dirty drinking water, unclean surroundings, and improper food cause many diseases in chicken. Clean the coop area and remove the poop and spoiled feed every day. You can purify the drinking water with turmeric powder or potassium permanganate. Feed chickens a balanced diet. Add some garlic or onion to the feed to build up their immunity. Leaves of bitter medicinal plants help to prevent intestinal parasites. Deworm the chickens with the help of papaya sap, betel nut or pomegranate fruit peel. Prevent calcium deficiency by giving the chickens some lime or crushed eggshell. Tie a small bouquet of aromatic leaves in the hen house to repel external parasites.