C&C Alternatives Cage made out of wood?

It can if you protect it against urine. I have one made from wood, the walls are oiled, and the ground and the lower (10cm) part of the walls are made/covered in some special treated wood that is already pretty water resistent. And the connections have to be protectet too! In my case it is this white glue that is mostly used for wood.

They need as much room in a wooden cage as in any other cage.

Wood will stink terribly if the urine gets to it.

You can get grids from Walmart -- order them online and have them delivered to the store for pick-up, and there'll be no shipping charges. Just be sure you get the ones with 9x9 holes, not 5x5.

You could build a wood cage and still put a coroplast tray in it as well

You could make a just coroplast cage- without the grids. Look up Piggiepigpigs on Youtube and look at her current cages (her most recent video).

Here is my cage until I can get a C & C Cage this is for 2 boys