Organic I believe, is a matter of preference. I would prefer to buy all my buddy's food organic, but sadly, that isn't quite feasible right now.
Theoretically, if you feed your dog veggies, it will be expending energy on matter that will have no positive effect for it. If anything, the digestive system will be wasting energy better used to actually retrieve nutrients from meat/bone/organ. (>insert something about doggy digestive track being much shorter than the human digestive track, there for more conducive to raw meat and much, much less conducive to veggies)
For references, explore(usually via Google
) "Barf", "Prey Model", and/or "RMB" raw food models to see if any of those fit for you. This is, if you haven't yet!
However, if you feel as though you wish to firm your dogs stool, Pumpkin/squash should do the trick. This 'trick' is also occasionally not recommended, as the pumpkin will mask your dogs stool, rendering any monitoring of the stool(maintained in order to ensure your dog is digesting properly) useless.
Another tip is to add a little plain yogurt to your puppy's meals, as a pro-biotic to aid healthy digestion if they may be having a little trouble.
Hope this helps!