Earlier last year I had a Whiteface Cinnamon Pearl
Pied pair begin to lay their first clutch of eggs for
me. I had been told by the previous owner of the pair that that they often
laid quite large eggs but was certainly not expecting the size egg they
presented me with for their first. It was not twice the size of a normal egg
but was certainly the largest egg I had even seen laid by a cockatiel. I
wondered about the possibility of twins but could find no information on it at
all.
I
candled the egg after a week or so and was surprised to see what definitely
looked like 2 embryos developing.
I contacted an avian vet and was told that in most cases the egg will
probably only be around 70% bigger than the normal egg and if this was the
case then it was uncommon that 2 chicks could develop normally and survive.
They did continue to develop and actually did get to
pipping stage. Because they had grown with one chick virtually on top of the
other there was only access to the air sac for one chick. Naturally it was
therefore impossible for both to survive and ultimately neither chick made it.
I did not intervene at all with the hatching because I was told there was
little hope so I let nature take its course.
After the first tiny pip mark on the shell all movement ceased and it
was obvious there would be no hatching taking place. I then decided to open
the shell and see what exactly was inside. As it turned out one chick had an
enlarged top of its skull as seen on the chick on the left side in the
picture of the 2 chicks. They were covered in down and everything else looked
to be properly formed.
If there is a next time I will endeavour to assist hatch
and see if it is possible for twins to survive.