The stress of such confinement can harm the cat's physical and mental health. (alleycat.org)
How to escape such confinement - by - truncated - reason? (firstthings.com)
Dogs and puppies are unable to express normal behaviours in such confinement (they have no space to exercise, play or explore) and this can lead to the development of repetitive behaviours, also called «stereotypies», and other psychological problems. (savehanktheneomastiff.com)