Posted by regina comaich on July 9, 2007

Q: Would an egg ready to hatch weigh more then an unfertilzed egg?

Habitat: suburban/yard

State: California

Habitat: suburban/yard

A: This sound suspiciously like a school science question Regina, but I'll try to help you out.

An egg ready to hatch should weigh a bit less than an unfertilized egg. Everything a chick needs for development is within the egg except oxygen (O2). As the chick develops, it absorbs the yolk (that's its food) and much of the water in the albumin (egg white). As you can guess, the chick does need to obtain oxygen and lose carbon dioxide (it's a living organism) so it gets the O2 it needs and loses the CO2 as waste through the shell pores. Along with the loss of CO2 from the pores, it also will lose a bit of water. Therefore, the egg just before hatching weighs a wee bit less than the egg before incubation begins. Make sense? I can believe in a science class that the answer is that it is the same since the difference is not great. However, I did ask a poultry specialist and this is what he told me. Check out one of our earlier units about eggs and eggshells at www.enaturalist.org Hope this helps you out.

John Wiessinger ( July 10, 2007)