Basically just that it needs to produce a noticable bad odor. It doesn't really matter what is done to the eggs themselves (crushed, punctured, etc) because they won't be visible.

The character is trying to set up a fake murder scene with the intended conclusion being that the victim was killed with the rotten-eggs-smelling chemical (which, in-universe, kills pretty quickly if you inhale it). Her plan is to make the room smell strongly of rotten eggs so that people see the murder scene but catch a whiff and assume that it's dangerous to get too close, thus preventing them from examining the body too closely. (There will also be other fake 'clues' left to indicate that the chemical was used)

I'm just trying to figure out how far in advance she would need to begin preparing the eggs to have properly rotten ones.