Hi everyone! I've been lurking for days. This is a great community. You sure know your chickens! So much to learn. I have 4 sex-linked black stars, 4 EE's, 4 Wyandottes, 2 Barred Rocks, and 2 Jersey Giants in a brooder in my guest bathroom to help manage heat and chick mess. They range in age from 2 1/2 to 5 1/2 weeks. I got most from a local farm and some from Agway. They are doing well so far and your posts have answered numerous questions over the past couple of weeks
) You have a nice mixed flock. Black Sex Links are friendly and hardy, egg laying machines. I've raised them for years (along with dozens of other breeds and hybrids), and they have been my best layers, consistently churning out more than 300 eggs per hen per year. You should get loads of eggs from those four girls. 
and Welcome To BYC!