it is only april. plenty of time for the hive to rebuild itself imo, and if they are there there is a good chance they will make a new queen if there are eggs to do it. instead of adding them to the stronger hive, I personally would add eggs and nurse bees from the strong hive to the weak one, do it a few times periodically until you see a queen being made, notching the cells can help as well. you may actually prevent swarming of the strong hive doing this, and you will then end up with two queens and two hives thus birthing twice as many bees as you would with one. at the end of the season, if the hive is weak, then you can merge them if you wish. But right now it is the time hives are building up and potentially swarming and you are doing your splits anyways.
for thoughts and ideas on the relative way to go about doing this, google or look into "OTS queen rearing" and understand the concept and ideas behind it.
here's a start: