I adopted 6 hens today that were hatched around Easter. There is an EE, 2 light Brahmas, a Black Australorp, a golden laced Wyandotte and a red hen, not sure if she is new Hampshire or RIR. I also have a flock of true ISA Browns from Townline hatchery that were hatched around 4/30, just 10 days later than these new girls I just adopted. The difference in size and maturity is significant and I'm wondering if in just 10 days my ISA's will change from looking like juvies to full grown hens. Can just 10 days make that big of a difference?