Most of the peeps on here don't keep males long...just long enough to get to butcher weight or age....so they don't worry about them getting too much calcium. If they intend to breed them then they should be feeding a complete and balanced feed ration of at least 20% protein but the better ration of 24% would be ideal. There is enough calcium in a 'gamebird feed' that no added calcium should be used/added, ie; limestone grit, oyster shell, etc. but many peeps do have it available to their birds at all times.
I raise mine in a very large aviary, there is no need to have calcium available for my birds, as the soil has limestone grit size particles and the soil is high in calcium. They get enough ca from eating the limestone grit. If they were on wire or in a cage that was above ground, then oyster shell, or a chick size grit could be used for extra calcium...if needed! ....as I said most gamebird feeds have a calcium level that is adequate.