I'm pretty sure nearly all schools have some sort of rolling admissions process.
There are a few that don't but can't think of any off the top of my head. You're just going to be better off filling out the secondaries in the order you receive them as soon as possible after you get them. (Some variation based on how easy it is to get them filled. Like if you get one that might take a while to fill...then do one that needs minimal work that you got slightly later).