The carved goose eggshell is made of over 4.000 drilled wholes.
I usually use a PROXXON microtool with a spherical ( 1mm) diamond mill. I don`t use stndard drills because it put too much pressure on the eggshell.
I trace the design with a pencil and then hole by hole for a long time. Of course some shells crack (sometimes after many hours of drilling), but if you are delicate and patient , you will be successful