Spaying female rabbits dramatically reduces cancer risk and prevents pregnancy-related welfare problems. Neutering males supports bonding and reduces behavioral welfare issues. Both procedures have strong welfare justifications.
The welfare case for rabbit spaying is among the clearest in companion animal medicine. A 50-80% lifetime risk of uterine cancer in unspayed does - with cancer causing pain, bleeding, and eventual death - is a compelling welfare harm that spaying eliminates. The procedure has some risk, particularly in rabbits compared to cats and dogs, but this risk is manageable with a veterinarian experienced in rabbit medicine and is substantially outweighed by the lifetime welfare benefit of cancer prevention. For males, neutering reduces the aggression and frustration of hormonal behavior and dramatically improves the prospects of successful bonding with a companion - itself a major welfare benefit. The welfare cost of not spaying or neutering outweighs the surgical risk when properly assessed.