That's to be expected. The life cycle of a bee is something like 30 to 45 days.
Mrs. Eagle has a small hive in our backyard. Of course we are always finding dead bees but the queen lays about a thousand eggs a day.
We live in a highly agricultural area of Northern California (soon to be The State of Jefferson) and we have cropdusters flying overhead all the time and we see, hear and smell the pesticides being sprayed all around us and her bees are doing fine.
Still not a fan of genetically modifying food so they contain pesticides and definitely not a fan of Monsanto suing family farmers and orchard keepers out of existence because of the cross-breeding of some of their GMO crops with natural crops.
You realize that all plants contain pesticides naturally?
Otherwise they never would have survived.