I quickly needed a fake egg to replace the ones my Kakariki laid. The size is 25x19 mm, just like the original. It should also work for smaller conures.
I placed it upright on the build plate and lowered it by 0.5 mm. This made it easy to print in Extrudr White ASA. After a bit of sanding, neither the bird nor my girlfriend could tell them apart. (Can you? Only one of the eggs in the picture is printed.)
The author marked this model as their own original creation.