Cells of pollen removed?

[Dexterjc]

As I was cleaning some dead bees from the screen bottom board of one of my hives, I found 30-40 cell shaped clumps of pollen. I am pretty sure that its pollen because each one is a different color of orange or yellow, but they are the size and shape of a cell, not just little bits of pollen. Why would they throw that pollen out?
Thanks!

[Michael Bush]

Pollen loses nutritional value as it gets older.  They probably decided to replace it with fresh.  It could also be contaminated with pesticides.

[stanisr]

Michael, could they be making room for brood?

[Michael Bush]

I'm not saying that they couldn't be, but they typically don't remove pollen, they consume it instead.