How is it that birds which lay a large number of eggs are able to have them all hatch on approximately the same day?

I'm asking since there's a friend of mine, who states that thanks to "biotin", thay are basically harmless, so he eats them 2 in a row.

How is it that birds which lay a large number of eggs are able to have them all hatch on approximately the same day?

Patrick Casement, London, UK

Welcome to this Friday's round-up of the week's top questions on The Last Word.

Questions this week have been overwhelmingly biological. Today, we're wondering what is happening to symphylan's tastebuds. When drinking well water after chlorinated water, symphylan experiences a strange bitter taste. Can you explain these tastebud troubles?

For a bit of entomology, Alisong found a 5.5-centimetre-long moth on her gatepost. There's been quite a discussion about it - take a look to find out what it is, or add more heat to the debate.

This one's not for the faint-hearted, but it's pretty egg-citing: take a look at what's hiding in the white of these chickens' eggs.

Ed_Harman was puzzled by his ability to sleep until exactly midday every day, irrespective of the time he goes to bed. Some of our Last Worders help explain why he awakes at the same time every day.

The exception to the biological theme was celliottuk's question: if you want to stop fizzy drinks from going flat, would it help to squash the bottles that contain them?The Last Word members strike again with explanations of what gaseous shenanigans are going on in those bottles.

If you have a better answer for any of this week's questions, roll up your sleeves and get stuck in. Otherwise, sit back and enjoy the explanations!

All the best,

Kat

Letters and comments editor, New Scientist

Description of image: It has a tiny hole in it (almost visible in the pic) and hairline fractures (not visible in pic). Image taken using a USB microscope. Found the object on my shirt cuff. it measures 0.9mm diameter and is spherical.

Whilst visiting relatives in Singapore we had a look around the Chinese & Japanese Gardens in Jurong.  I was intrigued by these pink egg-like masses which were stuck on just about every rock, stick or reed which made contact with the water surface of one of the ponds.  I couldn’t find anyone to tell me what they were.

One of my young chickens has just produced an unusually coloured egg (to the right of the photo). The egg on the left is more typical of the breed.

I know egg shell colour is variable, even in eggs laid by the same hen on different days, but how did one egg undergo such a sudden and distinct colour change?

Colin Booth, Durham, UK

At breakfast one day, my 4-year-old son was peeling his boiled egg when he noticed something unusual. On the side of the egg was an almost perfect white square with sides about 1 centimetre long. This was enclosed in an oval patch of yellow matter (see photo, left).

Although the yellow patch looked like egg yolk, the egg appeared normal when I cut it in half, and I could not see any connection between the egg yolk in the centre and the yellow patch on the outside.

Does anyone know how this formation was created?

Johan Forsberg, Linköping, Sweden