Being on starter 20% protein feed won't hurt them. They just don't need all that protein and you're paying a little more for it. Plus, that much protein causes them to continue to grow too fast, which can cause them to lay earlier. Laying early may seem like a good thing but when that happens, they then lay smaller eggs and don't lay as well for some reason. Not a big deal, most of this is just guidelines anyway, not really hard and fast rules. For example, I ran out of starter feed at 8 weeks so just switched my chicks then to grower food.
There is one feed thing you do want to avoid and that's giving layer food to chicks. Layer feed contains too much calcium and chicks can't process it at that age. It will damage their liver and cause major problems. So, if you ever have a mixed flock with chicks and adult chickens, the experienced people recommend feeding them all starter and then grower feed and adding oyster shell for calcium on the side for the adults to eat. The adults need the calcium to make the egg shells for the eggs they lay.
Not sure what that "puppy food" spell is, then, if you cleaned the coop and still smell it right after. One thing... I had 10 chicks 10 weeks old and then brought in an additional 6 chicks that were 8 weeks old. The new chicks smelled different, a little like puppy food maybe? The new chicks came from a hatchery which I visited to pick them up. There were maybe 1000 chicks of different ages there so a pretty high concentration of them in one place. So, the new chicks smelled strongly of, I guess, chicken! Eventually, the new chicks lost that weird smell and now all 16 chicks smell the same and much less strongly. Not sure if this is helpful but it made me think... how confined are your chicks? My 16 chicks free range completely and have a 10 x 14 coop which I clean the coop of droppings every morning. I also turn their straw with a pitch fork daily as well. So, there's only a very faint smell of chicken and it's a pretty clean smell.
Hope this helps,
Guppy