One of my top-bar hives was missing a queen, and for several days my wife and I were looking in the other three tbh's for a bar with eggs to give to the hive that needed to raise a queen.
I could see lots of capped brood, some we moved with the nurse bees over to the queenless hive just to build up the population. I thought that I could see the eggs if I held the frame up so that the sunlight shone on it; however, I couldn't see any. Finally I put on my "10X LED Head Headband Magnifier Magnifying Glasses Loupe Watch Repair LED Light" that I bought on Ebay for a VERY low price (also got one for my son)... but I digress. Anyway, I held up the same top bar that I had previous looked at for eggs and "...when, what to my wondering eyes should appear, but a miniature..." egg and several more. If y'all ain't got one, they's cheap on Ebay, and they shore do hep ya see those tiny, tiny eggs. I couldn't belive how small they were.
.................................. http://www.ebay.com/itm/10X-LED-Head...item51aef9a4d3 Check 'em out.