This one nearly caught me out. Probably because the cockerel is not doing the job he was intended for. He may have too many hens to service. I found that giving the cockerel a nice cup of Horlicks before he goes to bed, makes him sleep sounder and rearing for action in the early morning.
Hope this helps.
The domesticated hens have been selectively bred over the years to continue laying even when there is no rooster present.
The wild chicken's ancestor Gallus gallus only laid one dozen or so eggs and then incubated them, not laying again until she was ready to start a new brood.