Thanks for the feedback....one of the concerns I had was that Big Cheese has been "sold out" of Adult mice lately, and I just happened to find them available again on a given day last week, and ordered two trays. I weighed one of them, and figured in about 20 grams for the tray and packing wrap....the resultant "mouse load" came in at around 582 grams, or a little over 23 grams per feeder- which is a little bit on the low side of the advertised range. I guess I'll have to open one up to be sure....