Where did all my eggs go?

Hi all,

I have 17 pullets/hens that were hatched Feb. 1. So they're,...36 weeks old. They started laying at around 20 weeks, and within 3-4 weeks I was getting 12-14 eggs a day, every day. I was SO pleased and impressed!

For the past 6 weeks or so I'm getting 4-7 or 8 a day. It has gotten cooler, I know the days are shorter, but....I miss all those eggs. I've done a lot of research here on the boards using the 'search' feature; I read about giving more artificial light, but can't do that at this time.

if let totally to nature, (no artificial light) will it be spring/summer before they start laying as much as before?

I have also fed them cooked oatmeal with red pepper flakes but not consistently. Maybe a couple of times a week, only 3 times so far. Should I do this more often?

Any suggestions, advice, comments appreciated. These are my first chickens; my mom had chickens, my grandma had chickens but all I ever did with theirs was help gather eggs. These are my first ones that are mine to take care of.

SECOND Question:

Will the size of the eggs get any larger than they are now, at 9 months? These are Black Australorps and I was expecting large to extra large brown eggs. I would say that right now they mostly are medium to almost large. So I'm wondering if the eggs will get bigger. At what age is a chicken considered "grown?"

Thanks!