if u put in a close area.. for sure it will smell.. must put at place with nice air circulation .. i understand the smell.. as i have a house mate which seldom and now never clean his cage... until got mushroom   .. and his GP eat it.. i told he dozen of time ask him to clean his pigs.. but always say ok ok.. later.. it has now been 4 month...  .. then he stupid 1 also .. go close all the door and window.. causing the living room no air circulation.. where one day i come home open door to my house.. i almost faint.. the stink is unbearable.. complain to him.. but until now still not yet clean.. here is his cage.. and his kesian punya piggies.. sometimes i sedekah them some food..