How is the cage kept clean?
Plain newspaper is fine on the cage bottom. NEVER USE CAT LITTER! Canaries will eat it and die! Corn Cob Bedding must be changed every day. Damp Corn Cob quickly becomes moldy. The cage-liner paper sold in pet shops is fine, but most breeders use newspaper. As often as possible, disinfect the cage. Gently take the bird out and place it in a temporary cage. Then scrub the original cage with hot water and a disinfectant.
