Same issue here, blech on the mess and smell.
George the Cayuga duckling and 1 Spirit the EE chick are living in my living room, in a wire dog crate that has a layer of aviary wire and then a layer of plastic. The wire is to keep the cat and dog out and the plastic is to keep the shavings in and the water in.
It smells though, despite complete change of shavings every other day.
They are 5 weeks old, George is the size of a Mack truck and his mess is just that a mess.
Garage isnt an option here as its detached, no room and I would not be able to see them constantly.
Cannot wait for them to go outside and mess be gone from my living room.
I like your garage setup, nice pen!!!