I'm not sure about Georgia Giant specifically as I raise Butler bobs myself but according to a controlled study done by Susannah L. Clary of Manzano Valley Pheasantry and published in American Pheasant and Waterfowl Society a ratio of 1 male: 2 females gave the highest fertility in the common...
I use this list (link below) provided for the chicken folks as a good starting point for both the good treats and things to avoid.
https://www.backyardchickens.com/a/chicken-treat-chart-the-best-treats-for-backyard-chickens