Why do i get different amount of eggs?

[chickenlil101]

I have 9 hens and sometimes get only 4-6 eggs a day. One day i finally collected 9. Why is this?

 

[chickaddict]

I have 6 hens and get between 2-5 a day. I've never had a 6 egg day.
I think it is normal. If the average hen lays approx 275 - 300 eggs a year and there are 365 days. The do take a few days off.