Welcome to BYC, Terry. Glad you decided to join our flock. I've raised dozens of breeds and hybrids over the past 50 years, and I can tell you from experience that how many chickens you need for a dozen eggs a day, depends on the kind of chickens you have. Since sheer egg producing is a priority (as it has primarily been for me these past few years), I would suggest Black Sex Links (Black Stars). Sex Links are the kind of hens used by laying houses for producing their brown eggs as they are egg laying machines. I've raised Black Sex Links for years, and in addition to being hardy and friendly, they have been my best layers, consistently laying over 300 eggs per hen per year. If you get high yield layers like Black or Red Sex Links, or White Leghorns, you will only need 15 hens to get a dozen eggs per day under normal circumstances as these hens typically lay 6 eggs (occasionally 7) per week. If you decide go with Black Australorps, Rhode Island Reds, or Production Reds, I would up the number of hens to 18. If you go with any other dual purpose breed (Barred Rocks, Orpingtons, Wyandottes, Brahmas, Sussex, Hew Hampshires, Buckeyes, Faverolles, Easter Eggers, Marans, Welsummers, Barnevelders, Delawares, etc.), I would get 23 to 25 hens. Please feel free to ask any questions you may have. We are here to help in any way we can. Whatever breeds you decide to get, good luck with your flock.