What she writes about natural and "natural" environments is very interesting. From much limited exposure to dogs and cats, I have come to learn that they are happier when allowed and encouraged to be what they are -- some of my friends treat their dogs like children, not dogs, and the dogs seem confused and unhappy.
Dogs are pack animals; they need a pack and an Alpha -- oh! and a JOB! Figure that out and y'all and the dog will get on fine.
Cats, although I've had more to do with them, still are an enigma to me. I know they'll hunt when they don't need to do it to eat, that they need something on which to climb, and they seem to need a lot of stimulation. When they're not sleeping or eating.
There is a group here in NC calling themselves DOC -- Dogs Off Chains -- and they've made it their current mission to annoy the living sh*te out of folks who chain their dogs outside, claiming abuse and neglect and blahblah on behalf of the dogs. Their solution is "fences"; that's what they call them, although they're pens. They claim the dogs are happier, no matter how long the chain, in a pen.
I think they're happier inside with the pack.