The reason yours have not died yet is because they have not been eating "meatie" food and I would guess you dont keep a light on them all day. They are Cornish x and if hens, will not lay efficiantly. But anyway, I like your little barred guy!
Will they lay at all? Is it worth keeping them?
The little one in the background is a indigenous South African Koekkoek and she is my only laying bird at the moment