I've noticed with my Ein that a change in treats whill cause some gas, but will be gone in a day. Her system likes to adjust to things. I've also noticed that grains cause herto be really gassy. When we got her she was on a grain based dry food and was gassy! We switched her to an all grain free diet (accept the occasional treat with oat flour in it) and it's made a world of difference with the farts!!