The some breeeds take longer to mature than others start laying. You Hybrids like the Comets are breed to start laying early. If I remember the breeds posted corectly your Australorps will probally take the longest and also have the highest feed conversion. That is the amount of feed to grow up and make then make an egg. Not much hope for those roosters to pop an egg out Lol. Oh and welcome from Ohio...Have fun on the BYC