Improving egg size and laying frequency?

[phaethona]

My backyard free-ranging girls are 23 weeks old, we just got our first egg two weeks ago

the breeds are:
6 production reds
1 white leghorn
1 partridge rock
1 BSL
1 unknown, but here's a pic:

So I think we have three layers out of the 10 hens we have. So far in the first two weeks we've had a grand total of 7 eggs, and they're all really small. maybe I'm overly anxious, but I was thinking that we'd have more than that, and I want them to start getting bigger. Their daily diet consists of:
16% layer feed
bugs in the yard
B.O.S.S.
oyster shell available
about every other day I give them plain yogurt, cheese, cooked eggs, etc. as a treat

Is there anything I can do/avoid to help them along with their production and egg size?

thanks!

 

[Katy]

Egg size will increase overtime. As far as frequency it pretty much depends on the breed and the individual bird as well as their living conditions.

 

[gallusdomesticus]

Egg size does increase over time but their frequency of laying is dependent upon their 25hr ovulation cycle.; they can't lay any more often than that. Additionally, if they're stressed by heat or other factors, their laying frequency will decrease

 

[Katy]

This website has a chart that shows what you can basically expect from the different breeds of chickens as far as egg size and how many eggs they'll lay under good conditions.
http://www.ithaca.edu/staff/jhenderson/chooks/chooks.html