Non-urgent but troubling behavior query: post-neutered

Question
Background: 2 yrs ago we rescued a bunny couple; both estimated to be 2 yrs old; we had them neutered & spayed. They live indoors; have a caged area to sleep & eat with litter box & have weekend lengthy playtime on the grass in the backyard. One year later slight spraying observed by male; we didn't think too much about it. This spring he is spraying a lot, the hardwood floor, wall & door near the caged area is covered with urine splashes. AND now he is trying to mount the female frequently, more when they are in a confined space, but also chasing her sometimes went they are in the backyard. She runs away. (When he is not chasing/mounting they lay side by side peacably.) We started watching in March and now she even has a tuft of hair missing where he grabs her nape. Please advise. The vets we use are reputable & we have had 4 other bunny couples in the past 2 decades, but none of the spayed/neutered house rabbits ever reverted to sexually aggressive behavior after they were fixed. HELP! My husband says they will have to live in our backup  outdoor hutch if he does not stop this.

Answer
Dear Anisha,

When a bunny resumes aggressive/sexual behavior like this post-neuter, it is sometimes because of an adrenal tumor.  Fortunately, this can be treated with a chemotherapy drug, Lupron.  Please ask your vet about this, as it can make a big difference.

If that doesn't work, it's back to the drawing board. But this problem occurs more often than you'd think.  So I hope this helps.

Dana