rodent room

[reptilesalonica]

I am making a rodent room and i will need your help with the air flow exchange.
Below is the drawing of the space that will be used.

I will put a fan in the one upper end of the room.
I should put it to blow the air from the room, or to bring fresh air from outside?
Do i have to use another air pipe in the room?

For ex. i should have one fan to blow the air from the room outside and another one to bring fresh air from outside?

Have you done something like that before, and what is the outcome?

Thanks in advance.