My pet duck has been sick off and on since last April. The vet originally called his condition Limberneck. He took Meloxicam and SMZ TMP for about 2 weeks and recovered mostly. He could walk and eat on his own until it happened again about 2 months later. Again we treated him with the same meds. I have since learned that he may have had a vitamin deficiency, so we started giving weekly B12 shots per vet, liquid B12 in water bowl, and some other things. He has drastically declined in the last 2 days. I started Meloxicam 3 days ago at first signs of Limberneck and the SMZ TMP today for his fever. I have heard to use Ivermectin for the virus and possible worms. What is the dosage to use? Also I'm giving him BOUNCE BACK MULTI SPECIES ELECTROLYTE SUPPLEMENT along with plain water so as to not overwhelm his kidneys. How long can he take this?