Your protein question may be more of a animal protein vs. veggie protein issue not a % issue. Most layer feed is 16-17%, maybe 18% and flock raiser is usually 18-20%. Layer feed means it has extra calcium for egg shell production. There are pros and cons to each type of protein but ducks are really the only ones who do not do as well above 16% but if they free range at all it isn't much of an issue. You may just need to change up the diet or add a scratch block if your gals are indoors and bored. If you are using animal protein, try one without or vice versa and see if you notice a difference.