In a honey bee hive you essentially have three types of bees: workers, queens and drones. Workers are responsible for raising young, maintaining the hive, gathering nectar and converting it to honey, queens are responsible for laying eggs and drones are responsible for fertilising the queen.
A queen bee only mates once, although several drones may be raised in the hive. So many drones are raised simply to ensure that mating does happen, however almost all drones are extraneous to the hive’s needs. They are larger than workers, and raising drones put lots of unnecessary pressure on a hive.
In a sense, then, drones are unwelcome. The redundancy of drones is expressed in various behaviours. For instance, when winter comes drones are often driven outside the colony by workers to die of exposure.
Even the drone who successfully mates with the queen has a pretty tough time of it. Mating happens in the air (outside of the hive,) and the drone dies during successful coitus. The queen actually returns to the hive with the drone’s dismembered genitalia still protruding, and this acts a sign that a successful mating has taken place.
In terms of keeping bees, seeing many drones in the hive is a sign of a problem, especially towards the winter months. It’s also possible to control the genetics of offspring, artificially inseminating the queen with a particular drone from a specific hive. For more tips about bees and beekeeping equipment look online.