As I have said in several posts, I inherited a hive earlier this year and am just getting into beekeeping. I just reversed the hive today as it was the first day warm enough to do it and I hope they will make it after the cold winter. I saw a lot of dead bees on the bottom board (about two cups worth). I thought bees removed the dead? Also, and the reason for this post, I saw little grains of sand that were yellow in color on the bottom board and at the entrance. What is it, spent pollen? Just wondering if I need to be doing something with this hive or if I need to worry about it infecting my two nucs? Thanks in advance for the help.