Rabbit housing
Domesticated rabbits descend from European wild rabbits. European wild rabbits live in groups depending upon resources available. The more resources that are available, the less tightly they group, and actually prefer quite a bit of distance from the other rabbits. A literature review concluded that wild rabbits are either dominant or subordinate and the subordinate animals live in a constant state of stress and fear when in a group setting. Dominant animals require submission from subordinate daily, and if not performed, leads to violent fighting.
Domesticated rabbits allowed to live in colonies showed much aggression to each other, and the reviewers came to the conclusion that rabbits are very aggressively territorial animals and for their safety, should be housed individually. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5113872/