You can begin with this for an overview.
It's a dense read, and wont make much sense without some prior legal knowledge.
Otherwise, yes, I can link you to legislation and also interpret it for you, if that will suffice. It would be UK legislation. At your request, I'll waste my time doing so.
I know they've been thought of. They won't be done because they are expensive. It's makes more economic sense to kill them or castrate them. There is zero incentive for these people to do anything else. Non-human animals have no rights. Non-human animals are almost exclusively subordinate to economic interests, including animal "welfare" laws, which really exist to serve the interest of the property holders, not the animals themselves. This is a fantastic book on the subject.