The pre-mades are complete foods
You don't need to add anything else if you do not want to. You might want to give part of a chicken wing 2 or so times a week, to help clean his teeth, but that is only if you are comfortable with that.
The pooping less is normal, he WILL pool less on raw foods, as there is less waste, the body uses much more of the food than it does a kibbled food, pretty awesome huh? I love that about raw! We feed a TON of Stella & Chewy's and mine only poop 1-2 times a day, depending on the size of the dog.
Missing Link with Glucosamine is a good supplement -- as is Nupro with Glucosamine. I think the Nupro ingredients are slightly higher quality but Missing Link is what I use for dogs I show as it does encourage fur growth, despite no logical explanation for that.