Your guesses as to what may be wrong with the chickens?

[Aunt Angus]

Isa Browns and White Leghorns can somewhat commonly lay before 16 weeks too.

This hasn't been my experience at all, but every bird is different.

I'm sincerely sorry you are so frustrated. They are living beings, so I have never ascribed to the notion that all examples of any given breed or hybrid will develop or behave similarly. I am a small scale egg farmer, but I let the birds be and let nature dictate their productivity. Those birds will lay when they are good and ready. The pox may have delayed things, but I seriously doubt either are "duds." They may be late developers. My guess is that they will start laying when the weather turns.

My earliest layer ever was actually a Runner duck who layed at just over 16 weeks. I've not had any chicken lay that early. Doesn't mean it never happens, but I've had dozens of different breeds over the years.

 

[Mattl12]

This hasn't been my experience at all, but every bird is different.

I'm sincerely sorry you are so frustrated. They are living beings, so I have never ascribed to the notion that all examples of any given breed or hybrid will develop or behave similarly. I am a small scale egg farmer, but I let the birds be and let nature dictate their productivity. Those birds will lay when they are good and ready. The pox may have delayed things, but I seriously doubt either are "duds." They may be late developers. My guess is that they will start laying when the weather turns.

My earliest layer ever was actually a Runner duck who layed at just over 16 weeks. I've not had any chicken lay that early. Doesn't mean it never happens, but I've had dozens of different breeds over the years.

What I'm learning thus far is certain birds are just better producers, the best layers I have currently seemed to distinguish themselves before even laying, "Studs" for lack of A better term, yes I realize the gender reference is off but the right adjective is not leaping to mind. If I had to guess within the next few years genetic mapping of certain breeds will happen and their will be testing methods to optimize egg or meat production depending on the breed.

 

[Eggcessive]

If you look up any info on chickens, all of it states that chickens do not lay before 16 weeks old, and more lay after that. Some heritage breeds, and my own polish chickens laid much later. I have had ISA browns. They are nice layers, independent, and forage well. Mine layed eggs at 20 weeks.

 

[dawg53]

I've owned White Leghorns. As a matter of fact my very first birds were White Leghorns, raised from 3 day old chicks.
They were very skittish and could fly up on the roof of our house (until I trimmed their feathers). They were superb egg layers and early on, sometimes laid two eggs, but that eventually stopped.
The earliest they started laying eggs was after 18 or 19 weeks. They were from Ideal hatchery.

I've owned both Red Stars and Black Stars, I currently own Black Stars and they normally started laying eggs at 19-21 weeks. On the other hand, I've had one or two EE's start laying as late as 24 weeks.

 

[Mattl12]

Update, 1 of the 2 has now laid 3 eggs in 4 days. I say 1 because all 3 eggs have A very similar shape and size. Figuring out these 2 birds is A pain.