Why are only some of my girls laying?

[misidawnrn]

Only 4 out of 10 hens are laying. What is wrong with my other girls. 9 of my chickens are the same age and one is a few weeks behind so I know why #10 isn't laying. The first 4 have been squatting for a while and laying for weeks (about 4 dozen eggs worth) and they lay almost every day so I get 3-4 eggs a day.
Here are my chickens
2 Red Stars-laying
2 White Leghorns-laying
2 black Stars- occasionally squatting (rarely)
2 Blue Andelusions-just laughing at me, no really-they sound like hyenas with their laughing cackle!
1 Americauna-nothing
1 Speckled Sussix-the baby of the bunch

 

[ECBW]

What are their ages?

My RIR started on 22nd week. EE on 25th week. Silkie is still holding out. Some people posted that their hens starting at 18th week.

It seems there are many factors. The best thing is just have patience, although I am wondering about my silkie's gender.

 

[Nicole01]

Most likely it's due to their age. My now 4th layer just started laying at 26/27 weeks of age. I didn't get my first egg until 23 weeks of age. I don't mind the wait as long as they are healthy.