[jinglejoys]

Where I used to work they sometimes turned up (Mostly in hybrids) I called them Cocka Doodle Don'ts 

[sokel]

We had a leghorn a few years ago that layed eggs and sat them , she raised 3 clutches over 2 seasons, when the last clutch where about a month old we kept hearing a muffled crow and then by chance we herd it when we where down at the hens and we couldn't mistake that it was her as she was penned up and the cockerel was nowhere near.
She did lay still but continued to crow, she never mounted any other hens and she never hatched another egg out even though she did go broody and sit her eggs

[Steph Hen]

I have also read about crowing hens, mostly considered very bad luck!
One of mine mounts other hens, but I know she's still laying, and now I have cocks she's stopped all that. Interestingly, she was never that high in the pecking order either.

I'm curious as to what would happen if you added a cock to your flock..?

[chrismahon]

A friend of mine had a small bantam flock of hens and then one started behaving like a cockerel. When he introduced a cockerel the behaviour of the hen reverted to normal but the new cockerel completely ignored her.