Amazing luck to catch a late swarm and have it not only survive but apparently thrive. Too Cool
I certainly agree. If there is no forage available yet, start feeding TODAY
Spring (the first few dandelions) is when I like to begin KYBO (Keeping Your Broodnests Open) upon the first major inspection and clean up, by inserting empty frames between drawn, start adding supers and generally spreading the broodnest out as the colony expands, to inhibit swarming by giving them something else to do......make honey.