You dog could be getting softer stool on Wellness because it has fruits vegetables and probiotics. Purina has corn gluten and bi products, so whatever your pet was used to eating you have to slowly switch their diet to get their stomach used to a new food. You have to switch the diet on a 25/75 % or 30/60% ratio slowly switching the old food out and the new food in over a week for best results with least stomach upset.

I just switched my labrador puppy of 7 weeks from Purina Pro Plan to Wellness and she has been soooo much better. He poops were a little loose the first day, but at least they were no longer black in color. Also, if you pet has been vaccinated or dewormed that will effect their digestion possibly for a couple of days.

My other labrador of 11 1/2 years has been on Wellness for years and her coat is awesome, she is active and very regular. I asked my veterinarian which food she recommends and she said every dog is different, there are lots of good foods out there and Wellness is a great choice to feed your pet. I do give only the Super 5 dry food, I don't feed wet food. I'll continue using Wellness or find another food to rotate in/out of her diet every 6 other months which is also recommended.

Good luck.