I have a litter of 8 week old pups.........due to be rehomed this week, the trouble is they seem to all have upset tummies at the moment. I haven't changed their food or given them anything different, any suggestions on what is best? Should I fast them and see if it settles down? I'm a bit worried about letting them go to their new homes, should I just wait and see or ring them and explain?

Any advice gratefully accepted

I'm not a breeder, but I would have thought it would be better to keep the pups, till the upset settles down, as moving to a new home is strssful, and could make matters worse.
You could try adding natural yoghurt to their food. This may help settle the upset tums.

HTH

liberty