NO bug spray around your chickens... it can be extremely harmful to their health and I have heard way too many stories about chickens getting caught in sticky flypaper and dying... so that’s a very bad idea.
Mites and lice hide during the day and are active at night. If you want to know what you’re dealing with, wait until nighttime and then go into your coop with a flashlight and check under feathers for bugs. That’s when you’ll see them. Natural remedies are the best... the DE is very effective but it becomes inactive once it gets wet. I know you can also off apple cider vinegar to your girls (along with fresh water) and garlics twice a week to help with external parasites. Keeping your environment clean is very important... I clean my coops out with distilled white vinegar. That’s the safest cleaning agent to use around chickens.