a Black Jersey Giant, a Buff Orpington, a New Hampshire Red, and a Silver Laced Wyandotte...We decided on those breeds because, while they may only lay 2-4 eggs a week, they're apparently pretty hardy and have longer natural lifespans.
Were you also considering those points when you picked the breeds for your first flock?
Because in the photos of your first flock, only the brown one with a white tail is a high production type.