My book "Feeding Poultry" by G.F. Heuser (Norton Creek press) mentions molasses and says that molasses is a laxative and must not be fed in large quantities.
It mentions feeding up to 7% molasses, but the downsides are that it increases chick feed intake without increased weight gain, decreases hen laying, and the litter becomes damp from the wetter droppings (they drink more water) which causes more flies to come.
It doesn't mention maple syrup but that is some of what it says about molasses. I love that book- highly recommend it if you like to adjust chicken feed as a hobby.
Not sure about fermented feed. There is a fermented feed thread around here you might ask on.