Be VERY careful that you don't fuss with them during their sensitive days. I have one I pulled by mistake. I was VERY gentle with the frame the whole time, and returned it as soon as I noticed the cell. Still, when I checked on her day after hatch, she had bad wings, unable to attempt flight. This may have been me, maybe DWV, maybe something else... in any case, do be careful while they are changing. I don't have any other signs of DWV in my hives, so I blame the handling. Sensitive days are from capping day to about 5 days after. She will emerge about 7 days after capping (day 16 total). Day 5-6 (14-15 days total) is usually when cells are moved to nucs, just prior to emergence.