You don't show on your profile where you live. You might get away with less investment in feed if you live down south and/or on a farm. Where I live, wild turkeys range all over the hills. They cover miles of ground foraging for an adequate diet. Poults are hatched in spring, just in time for the flush of springtime abundance. If spring comes too late and/or unusually wet or dry, they die. Right now we're pretty short on turkeys from what I can see. Last spring? Ha! Blizzards clear up to May 23rd. Poor turkeys!
Anyway... There's no possible way you could get away with doing what you propose where I live. In order to develop properly and live healthy lives, poults need at least a 19% protein gamebird feed or equivalent. The only practical means of delivering that level of protein for most of us is with a soybean meal-based recipe. You could also use fish meal, but that's not easily accessible where I live. I do formulate my adult birds' feed, but not my baby-youth food. They get gamebird starter. Be sure to check the dates on the bag--hard to find sometimes, but they're there somewhere.
I studied up on fodder a couple months ago. The big claim is that you can turn a handful of barley (etc) into a quality high protein food. No one I can find has any documentation for this. It's possible that, for a brief period after sprouting, the availability of the seed's bio-available protein spikes, but also likely that, as it grows its roots and tiny first greenery, it uses this up and becomes lower in protein than the original seed. With a seed planted in the fertile earth, partaking of the sun, it would replenish its resources quickly. Unless you fertilize it, though, and give it more light than I can in winter, that can't happen.
Adding (trademark) Nutribalancer is good (if you can access it), but cannot make up for a lack of protein.
If you're really excited about growing your birds' feed, you might look into mealworm farming or raising black soldier-fly larvae. Don't go with earthworms, though. I don't know whether turkeys would eat them, but they can harbor a disease called turkey blackhead.
Early nutrition is vital to the long-term health and physical development of your birds, so this is a bad time to experiment. Sure, you can give them fodder, kitchen scraps (anything you eat), a handful of mealworms and/or black oil sunflower seeds (when their beaks are big enough). They especially enjoy and benefit from meat scraps including chicken and even turkey. (cooked only, of course) Do make sure though, that 90% of what they eat is at least 19% protein turkey/gamebird starter and later, a quality flock raiser will do. There are nutrients especially needed by turkeys that will not be prioritized in feeds meant for other poultry, but can be expected to be included in flock raiser.
