As far as keeping breeding cats in outdoor enclosures, if anyone disagrees then feel free to have a stud cat spray all over your house 24/7 or an in call female pee and poop all over your furniture just so that they can be kept indoors as house cats and fight constantly due to territory issues
Obviously caging animals in small metal cages is cruel but as long as an animal is well cared for, given plenty of attention and love and is happy then what is the difference in keeping a stud boy in a nice comfortable pen with a large outside enclosure and keeping a horse in a stable with daily access to a field? I never had my cats in outside pens and chose to neuter my stud shortly after he started to spray because he is also our family pet and we wanted to keep him in the house with us but that would have been impossible with him being entire. One of my girls sprayed when in call and had to be confined to our conservatory when calling, which needed cleaning every day to stop the smell of cat pee taking over the entire house! Breeding cats smell, fight and can be grumpy, they don't generally make good pets until they have been neutered and are no longer governed by their hormones. If a breeder is to have more than one breeding cat they will at least need room to separate their cats to avoid potential fighting and the unpleasant behavior that comes with battling for territory so effectively these cats will be confined even if they are kept in one or two rooms of a house rather than outside in a pen.