This 60/40 brown/white split cannot be extrapolated on a worldwide basis primarily because of enormous differences in the data for layer numbers in China. Estimates for that country vary by as much as 1000 million birds, from 1,350 million to around 2,350 million. This difference might be explained as reflecting the size of the commercial flock as against the total for all layers, which would include backyard birds. An indication of how difficult it is to asses the situation in China is given by the official figures for hen egg output in 2007 having been lowered fairly recently from around 26 million tonnes to a little under 22 million tonnes – a cut-back of some four million tonnes or 15 per cent.

However, looking at the IEC data, it would appear that, of the 2.7 billion layers recorded by the 33 countries supplying information about their flocks, some 1.6 billion (59 per cent) were brown eggers, while around 1.1 billion (41 per cent) laid white eggs.

But, on a national basis the splits between brown and white show great variation from 90 per cent or more brown birds in Australia, Austria, France, Hungary, Ireland, Italy, New Zealand, Portugal, Slovakia, South Africa, Spain and the United Kingdom, to similar percentages of white layers in Canada, Finland, India, Iran, Mexico, Norway, Sweden and the USA.

Do these percentages change much over time? Between 2006 and 2008, brown eggers appear to have gained ground in Argentina, Brazil, China, Columbia, India and the USA. On the other hand, white eggers seem to have become more popular in Belgium, Canada, Iran, Japan, Mexico, the Netherlands and Switzerland. However, as with all the data, it must be appreciated that in many instances, the figures are simply best available estimates, and that small changes between years may not be significant or indicative of a change in market demand.