Hi Rod.
Thanks for  your reply to my e-mail
You should check larvae (both drones and worker larvae for the presence
of Varroa mites. It is very simple to inspect a 10 square cm area. If
you inspect one hundred cells and do not find Varroa mites you might
feel better. However, a negative test is no assurance that you don't
have mites. Keep checking!
About those small bees. They could be robbers from a "small" bee colony
(other than yours). Also, bees which have been without food for a long
time get small guts and look smallish.  As soon as they get a good
engorging, they look bigger. However, engorging will not do anything for
the wings, they might look smaller in fact.
Good luck.
Dr. R.