Five sounds perfect, and I think four might leave you with less than you want each week. It is always nice to have some for friends/neighbors. We have 14 hens laying, and they each lay about 6/week in a perfect week. They are in their first year which is about as good as it will ever be, and it is spring, so we are sort of swimming in eggs just now...I love all of these pretties, but we really do have more eggs than I know what to do with. However, I give lots away, and we always have a few hens stop laying for a while. We've even lost two to flying predators, and every day they are out free-ranging is a risk we take in exchange for the freedom they have to run, forage, sit in a freshly pecked dirt bathtub, etc. So, for what it's worth, my question to you would be this: Are your hens to be free-range or penned, or a mixture of both? If the former, I would probably start with six to cover "Unexpected Things That Go Wrong". BTW, we have mostly mixed breeds of Australorps, Orpington, RIR, and they all lay extremely well.