It partly depends on how you feel about the impact on the backyard. Six of a breed that dig a lot make a fairly large coop into a bit of a lunar landscape (and that's in summer - more of a mud-wrestling pit in prolonged wet weather I'm afraid). So I am cutting down to four efficient laying hens out the back, and I have pekins (bantam cochins) out the front. They dig up the lawn much less, but have a shorter laying season. So I actually have more than six hens just now, but only four of them were chosen for their talents as egg-laying machines. I may have to buy eggs when moulting and things are going on, but I will still have heaps to give away in spring.