We have 17 layers giving us about a dozen a day. While 30 dozen or so a month sounds like a lot, we developed customers quickly and and several "regulars" we are keeping supplied. This helps pay for their feed and treats, so we feel (a little less than a year into the project of having chickens) that they are paying for themselves. We also give some away (neighbors who have done something nice for us, my elderly mom, a poor family we know, gifts, etc.). So we don't quite have enough for our needs!
However we need to add about three more chickens in order to keep up with our demand. Our coop is big enough but our pen really should be enlarged before we add more. We added ducks this year as well so I'm hoping that duck eggs keep some of my customers satisfied for the upcoming year.
Another issue to consider when building your coop is whether you are going to raise chicks. We need a section to close off from the other hens when we see one has gone broody. Our last broody hen was doing well, but we left her where she started, on one of the mutual nests. Unfortunately another hen felt broody for a couple of minutes as well and had a pushier personality than the truly broody hen and kept her off the nest for an afternoon. I kept trying to intervene but the whole thing upset the broody hen and she went off and forgot her eggs after that. All ten half-developed eggs were wasted because I don't have an incubator.
So if you want to see hens raise chicks, make a seperate indoor section in your coop where you could put water, food, a nest and have a little space for the young chicks to run around. They can't be by the older birds until they feather out, which could be awhile, so you might want this seperate part to have outdoor access/flap door to an outdoor pen designed specially for chicks. They can get through chain link and chicken wire isn't tough enough to predator proof anything.