These snakes are not out of there natural habitat. These chaps are born and bred in the UK. If a snake was picked up and dumped in what ever country it’s ancesters came from would most likely die (slow painful death) due to having no imunity are hiding, hunting skills for that new enviroment. Smugling snakes into the uk is not as big as the internet implies although it is a deplorable act. More birds and other fur monters are smuggled into the uk and europe.
Rabbits, gerbils, hamsters and dogs as well as a whole host of other animals are technically not in there natural habitat.
If you look after any animal right, it can flourish in any cared for enviroment. I don’t know any keepers who keep the snakes locked up for long periods of time. If you do, you should do something about it.
As for ‘Morbid food sources’ I take it that you are vegan? Snakes it meat, fish, insects. What’s morbid about that. It’s no different as to what humans eat (or cats, dogs, birds etc)
What happend to the fish?