ZairyMonkey t1_ityu9wo wrote

Oxygen and CO2 can pass through the shell. I learned this recently when hearing that one method for controlling the Canadian goose population where I live is to find the nests, distract the parents, and paint the eggs with a thin coat of cooking oil, which blocks the o2 in, co2 out process. The adults don't notice and continue caring for the eggs but they simply never hatch.