I just installed a solar powered rope light inside of my coop. I'm not 100% sure it'll affect egglaying, but I've heard that hens are usually more comfortable in coops that are somewhat lit, like a nightlight. This may be due to their vision, which is quite different than a human's. My girls...
I read some where that chickens can be afraid of the dark. I am putting some solar lights (rope lights to be exact) on the inside of the coop. I'm not expecting them to get a full 14 hours, but every little bit helps