He on Skinners duck and rice. He has to be careful what he fed as he is prone to runs. The thing is it is only after his tea he smells not after breakfast and its only been the last few days. He gets no tit-bits with food.
Sounds like he has found something rank to snack on then
As Spudlet says try some live yoghurt if you have some - if it continues try give him some aloe juice in his food - worked wonders for my friends boxer who has toxic farts!
My mum boxer had toxic farts but lab is beating him at mo. even he leaves rooms. I'll get OH to get some yoghurt when shopping tomorrow. Wouldnt suprise me if he eaten something he shouldnt
My dogs found some really rotten eggs once - dear god the gases eeking out of their butts for days were global killers!!!!
If it does persist it could be worth getting anal glands checked!!