|Source: National Archives, UK (Cat ref INF13/143 f13)|
During the war, the egg shortage in the UK was a major nuisance. There was dried egg powder coming into the UK from America, rationed at one package – the equivalence of a dozen eggs – every four weeks. You were only allowed one fresh egg a week, with extra allowances for pregnant women and small children. Before the war, the average consumption had been 3 eggs a week; the same amount as you could consume in the form of dried eggs during the war. This had not been equally distributed, though, so in fact, the poorer groups probably got more protein from eggs during the war than they had before.
In Sweden, eggs in cooking and baking were quite often exchanged for "SMP-white" (for egg white) and "SMP-yellow" (for egg yolk), but I'm not quite sure if that was made from eggs or something else – I seem to recall seeing something about it being made from milk rather than egg. Quite often, though, I find that the recipes recommend that you can exchange egg products for "egg colour", adding nothing but a little yellowish colour, so that any thickening must be left to flour or starch. That sounds bad, doesn't it? So one can understand the message in the poster above – save the scraps and feed the hens!