I have no personal experience of snuffles but as far as i'm aware if Baytril alone is ineffective you must not feel there is nothing more to be done, this is simply not true. A good vet will be willing to begin to pursue other options if the standard protocols don't work.
Pain relief can be tried in the form of a NSAID to reduce inflammation and swelling and help bun fight the infection.
A stronger antibiotic and a more appropriate antibiotic. But you would need probably a culture of bacteria taken from high up in the nose - this may be possible without anaesthetic but these swabs can be contaminated by the bacteria in the outer nose and may give inaccurate results, it is not always possible either to get the swab high enough in a conscious rabbit, and in a snuffly bun may not be such a good idea anyway. Provided the chest is clear a GA will enable a vet to reach the top of the nose by access through the back of the throat and up the nasal cavity this way.
However, I think your buns will need to be off Baytril for atleast 10 days in order to get an accurate result as current antibiotics have the potential to distort the culture.
There are many other antibiotics that can be tried from injectable penacillins, engemycin, cephalosporins, septrin etc but require vet discretion to administer for rabbits - hence the need for a good vet again.
I think Bisolvon is very useful for thinning the mucus in the nose and other respiratory passageways to allow the antibiotics to reach the bacteria.
Thumps has often explained the open connections between all sinus cavities, the eyes and the ears and that therefore there are many potential nooks and crannies for the bacteria to hide in. Some people find antibiotic eye drops access the bacteria that hide in the nasolacrimal duct.
A good combination of antibiotics both orally and systemically and even sometimes given via a nebulising chamber - appropriate for the particular offending bacteria - should help to reach all those respiratory pathogens hiding away in the far to reach areas of the connected sinuses.
Some other people have found adding drops of Echinacea to bunny's water can help to boost the immune system. It has certainly helped my bun with his allergic rhinitis.
Keeping stress to a minimum, fluids up, any pain under control, and a good diet to boost the immune system are all part of the holistic approach to helping bunny fight any infection.
Most importantly, this is not the end of the road and you have many other avenues left to explore before giving up on your buns so don't feel so disheartened. I'm sure there is something out there that can help. A good bunny-savvy vet is the best place to start. Good luck
:wave: