Here is Frank’s third photo.
“015 shows channels with healthy cocoons, but I’ve never seen so much bee frass!! The only part of the cocoons visible in the image is where the cocoon surfaces were tight against the base of the overlying tray. Othewise all the free space around the cocoons is packed with frass. Have you ever seen the likes of it?”
The Dutch would describe the frass to look like a sandwich spread called Chocolate Hail! Not as yummy though.
I have on occasion seen frass in these quantities. I think it means that these bee larvae were well fed and then produced lots of frass or bee feces. These healthy bees will have the energy to eat their way out of their cocoon and start a successful nest.
Another interesting item in this photos is those tiny pale blond spots all over the wood and over the cocoons. These are the pollen feeding mites. If these mites are not removed, mites wait for the bee to open the cocoon, the mite sneaks in and attaches itself to the bee- to set up house in the next nest.