Be sure students are using the proper grip, ready position, footwork, and recovery to ready postion If you have students form two lines, you can alternate feeding to each line, so that one line is the forehand line and the other line is the backhand line. Students can practice gently hitting the shuttle back over the net, with a net clearance of one or two feet. You may want to have some students take turns standing on your side of the net. Two students at a time can retrieve shuttles for you, so you can feed continuously. If you are using two or more courts, you can also have students take turns feeding shuttles to each other.
Quick footwork is the key here.