No, I would not. But animals are NOT humans. You can not use the same brush to paint all species the same. While dogs are gregarious creatures, it is not cruel to keep them in solitary confinement. Not ideal, surely, but they are not suffering. And they do get human companionship, minimal though it may be.
And incidentally, I do think poop size is an important factor for dog owners. As Dr. Fahley says, a basic diet can meet all their needs...but there is a LOT of undigested material that goes right through. That means food is wasted. Would it not be better to ensure they get the maximum amount of energy and nutrients possible from the food, instead of garbage going right through? Also, as we become a more crowded society, more dogs will be inside for periods of the day, meaning they must hold their bowel movements. If there is a lot of stuff going through, that is not possible. This results in upset dog, upset owner, and a dirty house. Extreme scenario being the dog is taken to the pound for messing--and voila, they are in a tiny cage with no socialization, and then, are put down if not adopted.
The basis for my reasoning is also that, not all animals are human, though all humans are animals. The perception is different, the reasoning is different. They do not have rights, per say, as we do. This does not give us the right to treat them cruelly or take away their basic needs, but demands that we fulfill their needs, while not diminishing our own. Animal welfare requires that these needs are met. Here, they are.
So whether or not his studies are enormously important (as we have somewhat differing views), the dogs are not unethically treated. Therefore I do not see the problem with his methods.