We have one hive, and have been feeding them for a couple of weeks, since having a dearth. We inspected yesterday, noting eggs, a fair amount of capped brood, and some new bees. Then, about 1/2 hr. after inspection of the hive, my hive partner noticed lots of bees around the entrance and fighting. I came back to find many dead bees all around the hive, and continued fighting all around. My partner had assumed correctly that this was robbing, so she put a wet sheet over the hive and blocked most of the entrance. We read other robbing posts on this forum, so are going to put up a robbing screen today, but were wondering when we should check inside the hive, for the queen and just check on overall goings on. Why would the queen be killed? Should we be feeding and watering our girls while we have the screen up? How long should we leave the screen up. Anything else we should watch for? Thanks for any help.