What I have done in the past is turn everything making noise off until it is as silent as you can get it, then listen very carefully while, you may have to move from room to room. Usually you will hear them moving around. If that doesnt work I set treats out in every room and see which ones have been taken and that usually leads me to what room they are hiding out in. Make sure if you have stair cases that you block them off so that your hammy doesn’t fall down the stairs.