What is happening now in the hives

Package bees. Right now every hive started with a package should be in two deeps. If you are running three deep brood boxes most beekeepers have them on. If not and your second deep is 70% drawn out, I would throw the third box on.
If you are drawing out comb, continue to feed.
 The hives are exploding with bees now and drawing comb is moving along at a more rapid pace. If you are running two deeps, I would put your honey supers on now. If the supers have only foundation, I would not put a queen excluder on the hive until you see wax and nectar on a frame or two in the super. Once you see the bees are working in the supers, then slide in the queen excluders. Check the supers every five days for progress.
 All hives should have the entrance reducers removed by Thursday. 90 degree weather is coming in and the bees will need to ventilate. Leaving the entrance reducer is when it gets that hot can lead to swarming.
Overwintered colonies should still be checking for swarm cells. Honey supers should be on. As the supers fill,  add new supers two at a time.
 The nectar flow is imminent. Be ready and good luck for a good honey crop.