Every year, EVERY year, every YEAR, there are multiple posts on beesource saying to the effect, "I installed my package of bees and they absconded."
If you feel like you must use a screened bottom board, KEEP IT CLOSED UP AT LEAST UNTIL THE HIVE IS RAISING BROOD.
I'm not going to try and pursuade you from using screened bottom boards, I'll just say I don't see a need for them. Use what you want, but keep them closed up.
If the mods do not care, I'll bump this post up every week or so in hopes of saving someone a package or two of bees.