It takes about 25 hours for an egg to go through the hen's internal egg making factory after the yolk is released. That egg can only be fertilized in the first few minutes of that journey. That means if the mating took place on a Monday, Monday's egg is not fertile from that mating. Tuesday's egg might or might not be, don't count on it. Wednesday's egg will be. Note that this is after a mating.
A rooster does not necessarily mate every hen in the flock every day but he doesn't have to. After the rooster hops off, the hen fluffs up and shakes. That fluffy shake moves the sperm to a container near where the yolk starts its journey. That sperm can stay viable in that container for 9 days to maybe more than three weeks. Most of us count on two weeks. So if you wait three weeks after a mating you can be fairly sure the egg was fertilized by the rooster you want but it's not guaranteed. Many breeders wait three weeks. If you want to be about as sure as possible, wait four weeks. Different people have different risk tolerances.
Hopefully that will help you plan.