[hedning]

> Eggs are one of the most efficient sources of protein there is.

Eggs aren't even one of the most efficient animal based sources of protein [1]. When comparing the energy input in terms of fossil fuels against the energy output in terms of protein broilers have a 4:1 ratio, while eggs have a ratio of 40:1. The same value for corn is 2.2:1. (which goes up to 3.1 when accounting for bioavailability).

Looking at total caloric energy input against output isn't any better (worse for the broiler, better for the eggs). We here get a 6:1 conversion factor for eggs, and 9:1 for broilers [2].

[1] Sustainability of meat-based and plant-based diets and the environment: http://ajcn.nutrition.org/content/78/3/660S.full [2] Land, irrigation water, greenhouse gas, and reactive nitrogen burdens of meat, eggs, and dairy production in the United States: http://www.pnas.org/content/111/33/11996/F4.expansion.html