I had a miniature poodle that had a terrible odor. We bathed her often, and she still stank. I sniffed at every orifice
and could not find the source. The vet diagnosed the problem as underactive thyroid, and the blood test confirmed his diagnosis. Within a few weeks on thryroid medication, she lost that nasty foul odor, and as a bonus, she began acting much livlier, and it was obvious she felt much better. Poor girl -- the vet said her thyroid was almost non-functioning. The thyroid medication was very inexpensive.