How are they this morning?
Photos of the chicks, their poop and housing may be helpful.
A few questions:
Do you still see active bugs crawling on the chicks?
What are you feeding them?
You mention Hot Shot being sprayed - was this outside in a well ventilated area?
Knowing your location is helpful as well (state?) this way we can help make better suggestions.
Vet care is always best.
Try to get all the chicks hydrated. Make sure they have plenty of ventilation and fresh air coming into their housing. If they were poisoned by DE, Sevin dust or Hot Shot spray, then likely they would be having respiratory symptoms.
Check their food to make sure it's not moldy and block off access to any plants that you think may be poisonous. Contact your local ag agent for assistance in identifying any plants you are concerned with.