Hi Everyone I think I know the answer to this question, but I want to ask here just to make sure. if(MSFPhover) { MSFPnav10n=MSFPpreload("_derived/Visually_Sexing_Cockatiels.html_cmp_brisbane-cockatiels-theme110_vbtn.gif"); MSFPnav10h=MSFPpreload("_derived/Visually_Sexing_Cockatiels.html_cmp_brisbane-cockatiels-theme110_vbtn_a.gif"); } Cockatiel chicks begin hatching after a 21-day period. As we can see, there is quite a difference in the incubation period between different species and it is often down to the female bird to sit on the nest. One or both parents may incubate. // -->. Large Fowl. // -->