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 fed 35% to some of our birds. Did they gain any better than the ones that got 30%? Not enough to justify the cost. And besides the extra protein is excreted so the main downside is the waste of the protein they cannot utilize.
The type of protein is very important as to the ability of the animal to metabolize the different sources available to the feed producers to use in their formulations. Turkeys seem to be much more sensitive to this than other birds.
It also isn't just the percent of the protein but the ratio of amino acids( most important is the lysine to methionine) that matters. Here's a good reference for you.
http://ag.ansc.purdue.edu/poultry/multistate/OpportunitiesforImprovingPoultPerformance.pdf
Also the physical structure of the feed makes a difference as to how much the turkey eats each time he bellies up to the bar.
In increasing order it is: whole grains, mash, crumbles, pellets.
I didn't mean to imply you were cutting corners. Everytime I hear someone is feeding scratch to a young poult I do assume it's because of the price. I promise to stop and think about that before replying next time.
Don't give up on turkeys, think of this as a very difficult lab experiment and the more times you do it, the better your results will get. Just don't get me started on those darn cornish x broilers. Now those will drive you crazy.
