Tray in Ventilated bottom boards

[Reginac1]

Okay so my husband and I are new to Beekeeping, he has went a bit overboard with it considering he said we would start with 3 hives and now have 21 hives many given to us or splits were made, but my question is we decided to try the ventilated bottom boards with trays and someone said to put oil in bottom of tray and it would help keep down SHB, but we have a lot of dead bees everytime I go to empty out the tray, can someone tell me if this is normal.  I don't understand why they go through the screen.  Any help would be appreciated.
Regina in TN

[rober]

i have a couple of the freeman beetle traps ( the plastic tray insert ). these came ( as an option )with my walter kelly screened bottom boards. even tho the slot is a tight fir the bees are still able to get in & i also had a boatload of dead bees in the trap every time i checked it. i cut a piece of 1/8" screen & put that in the trap. the bees cannot fall thru the screen but a vert few still manage to get in on the edges but the reduction in dead bees was significant.

[Intheswamp]

If bees are going through the screen then the screen mesh is too large.  If the screen mesh isn't too large then the bees are coming in through a gap somewhere and that needs to be closed up.

As to "why" the bees go through the mesh or through the gaps to their demise...only the bees know for sure.  But, they may be chasing beetles, they may be seeking other cavity areas to build comb, may be checking for other entrances,...

Ed

[rober]

the kelly sbb have 2 slots. the top one is for the screen & the bottom slot is for the tray. the slot extends into the front of the board so that the screen/tray is enclosed in the slot on 3 sides.they offer 2 different screens. 1/8" & 1 that is slightly smaller. i even tried taping the back end where the screen/tray is inserted. they cannot get thru the screen. i cannot figure out how they are getting in but they are. putting a piece of screen in the tray fixed the problem.