Statistically speaking, the best laying breeds are White Leghorns and Black and Red Sex Links (sex links are actually hybrids rather than breeds). These are the hens used by laying houses (White Leghorns for white eggs, Black or Red Sex Links for brown eggs) as they are egg laying machines, churning out over 300 eggs per hen per year. My personal favorite chickens are Black Sex Links (Black Stars), which are hardy and friendly, egg laying machines. I've raised them for years (along with dozens of other breeds and hybrids) and they have been my best layers, being especially persistent in really cold weather when the lay rate of my other hens has really dropped off.