I know this has been asked before, but...

I got four Leghorns that are a year and a half old two weeks ago. They've only laid about 7 eggs in the past two weeks. I know it's been asked before and I'm TRYING to be patient, but I want to make sure there aren't other things I should be doing. They get to get out of their pen and free range in the late afternoon, all day on the weekends. I'm feeding them laying pellets and oyster shell calcium, and the occasional kitchen scraps which they love. I have a fairly small "coop" that I made from a dog house, per Mother Earth News instructions. I'm worried that it's too small and I'm planning to make them a new one, hopefully next weekend. In the meantime, can a too-small coop be the problem? They go in it every night on their own. Thanks!