I have been trying to find the same answer for awhile now on exact nutrients with no luck. I saw on a vet's website that they recommended the month before hatching boosting overall nutrient cosumption. I'm planning on this spring the month before I collect eggs for hatching to start all of my breeders on Rooster Booster to see if there is any difference in hatch rate. I'm the nerd who likes to document everything so I already have my abstract write up, previous findings, theories and format for documenting the spring hatch to compare with prior hatches