Friday saw me collecting my one thousandth egg from the coop. I can't pretend that it looked a great deal different from its nine hundred and ninety nine predecessors. The same elliptical shape, the same brownish eggshell and no doubt when I crack it open I will be met with the same orangey coloured yolk. Still I suppose consistency is what one wants in the matter of egg production. That said it would perhaps be nice, whenever the present octet of chickens have entered their celestial coop to replace them with a small selection of breeds which would give me a variety of egg colouration.
Depending on breed the shells of chicken eggs may be blue or even olive green as well as the more normal white or brown. The principal component of eggshell is calcium carbonate which is naturally white. If there is nothing else going on in the chicken's nether regions you end up with a white shelled egg. With some breeds and indeed most commercial hybrids the hen releases a brown pigment just before the egg laying. The origins of the blue egg seem to emanate from a South American chicken which became infected by a virus which prompted a genetic mutation resulting in an accumulation of a blue pigment. I have read that the crossing of a brown laying breed of chicken with a blue egg laying breed will provide one with progeny which will provide green coloured eggs. I wonder if Chas Darwin realised that when he was writing, "The Origin of the Species."?