Some chickens aren't laying?

[northwestchick]

Hello,
I bought 10 chicks on September 15, 2015, 8 survived. They are now all very nice looking hens. I also have two hens slightly older than they are. Some of my chickens are not laying any eggs yet. Why is this? I know the weather is crazy in the pacnorwest. They do receive extra light as well. I will post some pictures in the comments.

 

[azygous]

It depends on the breed when they will reach point of lay. The larger breeds, and it would help if you tell us the breeds of your hens, don't reach point of lay sometimes as late as nine months of age.

Generally, pullets will begin to lay, on average, around age six months. Yours are ripe to begin laying anytime unless the non-layers are large breeds such as Brahmas and Cochins in which case, you may have a few more months to wait.

 

[northwestchick]

Here are the breeds:
Buff Brahma
Light Brahma
2 Easter Eggers
Buff Orpington
3 Welsummer