If they germinate sporadically over several weeks (or months sometimes) it means a percentage of them have seed dormancy. That's where refrigeration comes in but dry refrigeration isn't effective. They need to be refrigerated damp, such as in damp vemiculite, damp sand, damp perlite, damp coffee filters or other media for a few weeks before being started at room temperature. If you do that they should all germinate together within a week or two after coming out of the fridge. Not everyone has seed dormancy in their daylily seeds which is why there are always conflicting opinions on this but basically if they sprout erratically over weeks or months then you do have seed dormancy. You can either put up with it if you don't mind waiting, or damp chill them prior to starting to avoid the delay.
