I have been icubating my own eggs this year and it has been pretty fun, but I don't have as many fertile eggs as I would like to have. I have 1 Rooster and 21 hens. is my ratio for hen and rooster too low? Do I need another rooster and if yes, how do you introduce another rooster to the family? My rooster is RIR, 12 RIR hens and 8 Barred Rocks. Thanks for any advice!!