Find All Singing Mice

The first group of three singing mice can be found behind trash bags and a trash can to the left of Marge's Chippie, near the parking lot.

The second group of three singing mice is located near Rog's Veg Hole, next to the Oily Baps food cart. Hit the trash bags and trash can.

The third group of three singing mice is found in Sam's Ham shop. Head all the way left until you hit the trash blocking the road, then follow the houses to the left until you reach the van food stall. The mice are near the flower stands outside Rog's Veg Hole.