The fries are definitely prepared more frequently -- biscuits too -- but the sides are not what I would call the best part of Popeyes because they can be made in bulk and put under heating lamps for longer periods of time than say, chicken.

I don't know how quickly the chicken turns over but it's pretty consistent -- especially if you're ordering something specific (X number of legs, Y thighs, Z breasts), because they need to ensure the proper quantity and that may require breading and then deep-frying the chicken on-demand.

The seafood is probably more "prepared to order" than anything, but I honestly don't know. I've never worked at a fast food restaurant, I'm just a giant and unabashed fan of trash food.