[edstrong]

One of our hens, a five year old Speckledy called 'Tog' has started crowing. She has also become rather larger, with a big bright red wattle and has now started to develop sharp spurs on her legs. She is turning into a cockerel!

I didn't realise this could happen but apparently it does, though rarely. Something to do with hens only having one functioning ovary, so if this fails the other dormant ovary can grow into an ovotestis with resultant changes to the hen's hormones. The other hens are being quite accepting about her change and aren't treating her any differently, which is nice.

Has anyone else had this happen?

Here's a video of her crowing! https://youtu.be/kIG_Yx1ZuEI

[chrismahon]

We've had this happen often. Usually when they stop laying, but we have a Leghorn who crows (badly), has very large spurs, does a stomp dance around the other hens and is still laying! We also have a solitary 11 year old Wyandotte, who kept herself to herself until her lifelong companion died. Now she comes out of the coop and crows every morning. Whilst we only have two cocks, it can get very noisy here.

[doganjo]

Yes, I had a hen that was laying regularly change into a cockerel over a period of only a few months.  Gradual drop in egg laying then physical change over a few weeks

It also happened to a Shetland duck I had, and I also had what I thought was a drake start laying eggs

I think every animal, including ourselves have a very finely balanced level of male and female hormones which can change level at any time

[in the hills]

We've had one, too!

[macgro7]

It happens to hens sometimes (usually older) as well as pheasants - they start growing male coloured feather, spurs, Stuart crowing and stop laying eggs. It is caused by damaged ovaries