Ground rent creates a better environment: more parks, more forests, more wildlife.
Ground rents make people richer. Rich people have more leisure to care about animal welfare. They like pets, animal charities, and higher quality food (more likely to be organic or outdoor bred than factory farmed).
Ground rent pays for any desired investment. So existing welfare laws will be better enforced.
Ground rent lets you choose your ideal government: choose one that cares about animal welfare.
Faster economic growth brings more scientific advances. When artificial meat is better and cheaper than "real" meat, the economic case for abusive factory farming will disappear. Animals' only value to humans will be their beauty and companionship.