I want to preface this by saying I have not used this before so I can't vouch for its total accuracy, but it kind of goes in line with Fiasco Farm's oral Sulmet dose for goats, so it seems to be right. Use at your own risk.
First, I found a site with an oral dose for preventing coccidiosis, which is 1/10 cc per pound of rabbit. It seems that wouldn't be enough to treat an active case of coccidiosis, so I asked on a Facebook goat group and found someone who also raises rabbits. They suggested the following oral Sulmet dose for rabbits:
.5cc per pound for the first day, and .2cc per pound for days 2-5
This five day treatment would be used only when you have an active case of coccidiosis. If you want to prevent coccidiosis by dosing rabbits with Sulmet in water, the general consensus seems to be follow the instructions for dosing chickens, which is found on a bottle of Sulmet 12.5% solution.
When would you need to treat? If your rabbit exhibits the clinical signs of coccidiosis:
- weight loss
- loss of appetite
These symptoms are pretty common in other rabbit ailments, so not all cases of rabbit sickness will be coccidiosis. Check with a mentor or join a community you can talk to if you aren't sure when to treat for coccidiosis.