(http://www.honeyshop.co.uk/feeding.html) There are times in the year when the feeding of bees can be beneficial or essential.
In the Autumn after the honey crop has been taken off it is necessary to give sufficient food to see the bees through the winter and into the spring when nectar will be available again.
In early Spring when the bees have come through the winter but have minimal stores, not to feed them would cause a check on their expansion or even result in the starvation of the colony. Remember, hives that starve rarely do so in the winter but in the early spring. Spring feeding results in more bees and if you feed unnecessarily at this time of year you may encourage the tendency to swarm in May. Check in early March by lifting the hive at the rear, if it feels light they may be in trouble and need feeding or a more detailed inspection.
Freshly hived swarms need feeding to stimulate wax production and replenish the bees who have been living off what they could carry during the swarming process. If not fed they may decide to leave or take time to establish themselves.