Optimal UVA/UVB dosage/bulb/fixture for bunnies in indoor hutches during heat waves

[cwebster]

We have three bunnies in indoor hutches. It is dark in the room. Usually I put them in outdoor cages half the day every day most of the year. For the next two months, it is too hot (90-110) so am having to keep them indoors. Am seeking floor lamps that will hold uva/uvb bulbs but don’t know what dosage they need. I have read that the lamp should be 9-15 inches away and that they need a minimum of 20 min per day. One bunny, Dutchess, had terrible tooth problems until I began giving her daily time outside. The tooth problems disappeared. Recommendations would be really appreciated. Thank you!!

 

[JBun]

Needing sunlight would be for the vitamin D, which vit D affects calcium levels and so a rabbits bones/teeth. For most rabbits that get daily fortified food pellets with added vitamin D, getting sunlight wouldn't seem as essential, provided the rabbits are getting an adequate amount of vitamin D from the pellets and the pellets aren't too old with degraded vitamin content.

Your rabbits dental issues seeming to go away with time outside, could that be related to being able to eat fresh grass and forage while outdoors, which would provide added tooth wear from this vegetation? Or is your rabbit not eating significant vegetation while outside and you feel the improved dental health is directly related to the exposure to sunlight?