Claire and … cockatrices?

July 23, 2009 § Leave a comment

Well we now have a reason why Claire has stopped laying. To add to the chaos and confusion … she crowed today.

Twice.

Yes, really. As in “rooster”. Complete with the whole rocking backward and craning neck upward bit – Jo saw her do it the second time (which was about a minute after the first strangled attempt).

Argh. We’ve been wondering about those obscenely luxurious wattles and comb!

Claire the rooster

Is that the head of a hen? Opulent comb, wattles and lobes.

For those of you who are thinking something along the lines of WTF, here’s a brief bit of folklore, followed by some science.

Historically there have been numerous folk-stories about roosters that laid eggs, and were put to death as being obviously the spawn of Satan. (Which fits with Claire’s mood at the moment!)

According to writers as far back as Pliny, every so often a rooster would lay an egg. And not the sort that you’d be advised to have for breakfast – these eggs hatched into one of the most fearsome of mythical beasts – the cockatrice.cockatrice from wikicommons

“For they say that when a Cocke groweth old, he layeth a certaine egge without any shell, instead whereof it is covered with a very thicke skinne, which is able to withstand the greatest force of an easie blow or fall. They saye, moreover, that this egge is layd onely in the Summer time, about the beginning of the Dogge-dayes [between early July and early September], being not so long as a Hens Egge, but round and orbiculer:…sometimes of a yellowish muddy color… and afterward sat upon by a Snake or Toad, bringeth forth the Cockatrice, being halfe a foot in length, the hinder part like a snake, the former part like a Cocke, because of a treble comb on his forehead.”

Now it’s time for some science. In chooks, only the left ovary is functional, and the right stays undeveloped from the embryonic phase. If something happens to the left ovary to make it non-functional, the residual tissue of the right ovary will take over.

Which is where it gets weird. In direct contrast to mammals, with birds the male is the neutral sex – in other words, all embryonic chicks start out male, and only become female when the left ovary starts secreting female hormones. So when that stops happening, there’s a good chance that the vestigial ‘male’ tissue in the right ovary could produce sufficient testosterone to give the hen male sexual characteristics. Technically this is “genotypically female but phenotypically male.”

There’s apparently a lot of variation in how far this goes. In some cases the hen behaves like a male, but may still lay eggs. In more extreme cases she may develop fully male plumage, adopt male behaviours and even attempt to mate with the other hens. In the most extreme cases, this has apparently  resulted in fertilised eggs … The technical term is “spontaneous virilism”.

A quiet life – we must try and have one some day …

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