Last week I went to clean the bottom board of my 9 Hives; on the floor of each Hives, I clean out about one inch of dead bees...!since that, I am very worry about my bees.

What is going on in this Hives? It is my first year with bees. I live in north of Quebec. I feed my bees in Sept., I insulate the Hives and keep a small opening on the upper part to let the humidite to get out I treat againt the varroas in Sept.....

If someone know what is wrong whit my bees
please give me the info.