I hear you about the "helpful" feed store people. They may mean well, but sometimes they're like a used car salesman in that what ever they have in stock is exactly what you need.
You can feed too much protein, but guess what? It is still not an exact science as to how much is too much, we have...
It's my opinion that they are not getting enough protein.
Action plan: No treats, take away the scratch grains, go and buy some gamebird starter (min of 28% protein, 30% if you can get it).
The BBs are meat creating machines but you have to give them the fuel they need. Of the kids that...