A hen can lay eggs without a cockerel.
In my experience, a flock of hens is a much more argumentative place without a cockerel. They naturally establish a pecking order to create the alpha female, but the process is far less aggressive if an alpha male is in attendance. My various hens have been happier and more content with a cockerel present - and happier hens lay more eggs; well, allegedly.
Personally, I love cockerels. They're noisy, eat loads of food and don't contribute to the household food supply, unless you rear them deliberately for the pot, but they do protect the hens in a gentlemanly manner; they do find them food and cluck to call them over to it - all of which I find endlessly amusing and very sweet.
If you see a bird that's stands regally and has beautifully groomed feathers shining in a dazzling array of colours - that's a cockerel - overseeing his domain and looking damn fine whilst doing it. They're just so, well, eighteenth century dandy. A beautiful sight to behold and a pain in the ass at 5am in the Summer. Cock-a-ruddy-doodle-do. Anyway, don't say I didn't warn you!
