My 9.5-week-old puppies (small breed, 5 to 6 Kilos as adults, see Avatar) are having "soft" poop for a couple of weeks now.  It is formed, but you cannot pick it up very well, as it is too soft for that.  It is not diarrhea, it is just soft.  They act totally healthy and full of energy, and I wormed them together with their mother every two weeks since birth, the last time being on January 17th.  I used two different worm preparations:  Welpan (the first two wormings, age 2 weeks and 4 weeks) and then Milbemax (at 6 weeks and 8 weeks).  I have not changed their food.  They are not quite as enthusiastic about it as they used to be, and so I once or twice gave them a very similar food (canned, chicken and rice or potatoes, high quality, gluten free), and the poop immediately got soft.  It seems never to have returned to the nice, pick-upable poops they used to have.  Gardia comes to mind, but they do not exhibit the symptoms of Giardia in puppies.  Any ideas?  Any advice?

Are you giving any milk, as pups become less and less tolerant.

Worming will irritate the bowels so that could be it.

Overeating and fast food transit will do the same.

Chicken wings would firm up the poos.