like josh says
it can only dissapear for 2 reasons and 1 error
reasons
it does not exist in database
it does not exist in itemtype.dat
or your icons are just bugged but easy to check if you can manual open it
(i mean the picture in the picture folder)
so check if the id's are existing in the database ( the 4 stages , the egg , first evolution , second and third evolution)
check if the same id's exist in itemtype.dat or in the client folder
if they both do exist , then it need to be cq_action that it gets a differend id then the id you gave them after hatching ( also known as invinsible items and they happends if the id does not match with the pictures you have)
hopely this helps you
Greets From PowerChaos