Hi.
I'm glad you asked!
22% protein has been shown to give the best hatches, according the the studies I've seen... and I hatch up a storm!
That being said... eggs AREN'T high in protein, contrary to popular belief.

They actually are about 12% protein and 30% fat. Though they are a good source of vitamins and minerals including selenium.
To get your BEST hatch.. skip the scratch. It's diminishing not only your protein level but also you nutrient level... being vitamins, minerals, and importantly the amino acids.
Adding a vitamin supplement like poultry nutri drench can be beneficial (never more than 10 days straight for any supplement)... or even switching to 20% protein flock raiser and putting OS on the side for your layers. Makes it real simple to feed the whole flock including the chicks. Since I'm always hatching, have broody's, molting, layers, juveniles... I feed Purina flock raiser (it what's available at $17-20/50#) for the entire life of every bird here. It has worked well for me.
Dual purpose layers will do best on about 18% protein as 16% is the
minimum for light bodied layers like leghorn. In addition, the *usual* 4% calcium in layer CAN be too much for any bird not laying like roosters, broody's molters and so on. It *can* (doesn't mean will) actually cause gout or kidney failure if fed long term to those not in lay. Though it's most likely to happen to those who are somehow genetically pre disposed to it... it DOES happen. That's one reason I personally avoid layer. Plus even though the higher protein formulas are often a little pricier... OS is cheap and 4% (3% more than other feeds) So providing it on the side and getting more protein in my feed... seems to at least even out and NOT cost me more.
Of course you may be fine, just as you are! This is my experience and preference, as a major over thinker and (rarely achieved) perfectionist.
Happy hatching!
