Canker in general refers to a protozoal infection- neither amoxicillin (antibiotic) or otomax (topical antifungal, long acting steriod & antibiotic) will kill this organism. Thrush is a fungal infection (candida)- amoxi won't treat that. Otomax might be helpful- but it also has other distinctly unhelpful for a fungal infection stuff in there). Classic canker AND thrush don't tend to be in the ear- they like moist places- like the mouth/inside of beak, throat and crop. Stinky ear crud sounds more like an abscess, and a chronic one at that. Head tilt implies that the pus is already in the middle ear. Ideally this bird goes to a vet who will look at the crud under the microscope- relatively easy to tell the difference between canker, thrush and bacterial infection if one looks at it microscopically & stained properly for the yeast vs bacteria part. Peter Brown is not a vet, he works for a company that sells farm and pet supplies. E-mail help can only get you so far. In any event, it sounds to me more bacterial than anything else- but only hands on diagnostics will tell you for sure. If bacterial and in the middle ear- it needa to be cleaned out and appropriate systemic and topical antibiotics started. Don't put corrosive things into the middle ear like peroxide or drying ear cleansers. Use something gentle like saline or trizEDTA from the vets office. If this is a beloved pet chicken, and you can fund the visit- go to the vet, get them to look at the crud under the microscope, and even culture it if they think it is bacterial.
