Eggshell thickness and porosity in budgerigars and their relationship to hatch-ability

Abstract

As part of an investigation into low chick production in relation to the number of eggs laid by exhibition budgerigars, a study was carried out into the role, if any, of shell thickness and porosity to water vapour. Shell thickness was the same in clear eggs, fertile eggs, those containing dead-in-shell embryos and those with desiccated contents, and averaged 0–2 mm. Shell porosity was found to be the same in most clear eggs, fertile eggs, eggs in which the embryo had died very early and eggs containing an infected dead-in-shell chick. These had an average water loss, under standard conditions, of 1–54 per cent of the initial weight per 24 hours. Non-infected dead-in-shell eggs lost 0–27 per cent, eggs with desiccated contents, either an embryo or clear lost 7–95 per cent and cracked eggs, 5–64 per cent. The results indicate that some budgerigar eggs have an abnormal porosity to water vapour and that this may affect their hatchability.