9lb Boston Terrier is about 4 months old and has never consistently had a good firm poop. Breeder had him on Purina Puppy, but I switched him to Nutro Natural dry kibble for puppies pretty much right away. I think we may have switched him over a little too fast, but his poop was immediately a little firmer for a few days before it became watery again.
I did a little more research on the food and decided it was too pricey for what it was -- much better foods out there. To calm his stomach, we put him on boiled chicken and white rice; his poop got better for a few days, but inevitably started to turn into mush again. After a little more due diligence, he's now on Chicken Soup for the Puppy Lover's Soul. We phased the chicken and rice out over three weeks or so lessening the amount of rice and chicken day by day. We feed him about three times a day, about half a cup each serving. For lunch I sometimes feed him a little less than half a cup.
We don't have a lot of grass around, so he ends up pooping all over the sidewalk and as you can imagine or experienced, it's not a fun clean up. I constantly wish I had a hose in my pocket. Should I switch foods again? Grain free? Give it more time?