Luku---My first thought with foul breath is Periodontal Disease, but your guy is alittle young for that.....Now, it is possible that something is lodged in a tooth/mouth causing the foul smell.
If your noticing any unusual drinking water symptoms, then you need to have him evaluated (With Bloodwork) for Kidney Disease--This also, causes a terrible odor.
Next- Digestion problems cause odors that come from the mouth....And it can be foul!
Because you speak of poor coat, smell & ear problems, & mouth odor: I'd FIRST evaluate the food your feeding....This ALL may be a nutritional problem from feeding a low quality food....You need to start there & also make sure your NOT overfeeding......Let me know what you think......Karla
There's no vomiting and his poop is fine! His breath smells like a dead animal though, and Ive checked his gums and I don't see anything unusual.
Welcome---Any Vomiting or diarrhea? What does his breath smell like exactly? Also, what does his poop look like? Thanks, Karla