 The eggs are oval , white and coarsely textured . All species normally lay at least two eggs ; the usual clutch size is one to three , rarely up to six . Both sexes incubate with the eggs on top of or below the feet ; they may display when changing shifts . Incubation takes 30 – 36 days ; hatching success for undisturbed pairs can be as high as 95 percent but , because of sibling competition or siblicide , in the wild usually all but one nestling dies within the first few weeks ( later in the pink @-@ backed and spot @-@ billed species ) . Both parents feed their young . Small chicks are fed by regurgitation ; after about a week they are able to put their heads into their parent ’ s pouch and feed themselves . Sometimes before , or especially after , being fed , they may seem to have a seizure that ends in falling unconscious ; the reason is not clearly known . 
