They go by their shed cycles and the preov shed is normally 9ish weeks before ovy, then 2 to 3 weeks until prelay shed then 27 to 35 days on average until eggs.
You can't have a preov shed 2 weeks to 2 months before eggs are laid, that's just not possible.
Depending on the size of the female it takes 10 to 12ish weeks from preov shed to prelay shed, then 27 to 35+ days until eggs.
There seems to be this notion that they don't follow a certain guideline.
For the most part they are fairly predictable, there is "from what I hear" females that do things differently, but in all of the clutches I've gotten in the last 5 years not one has done anything out of the normal shed cycle.