Colony Breeding cage

Hi. So I was thinking about starting a breeding colony in my big 4ft x 7ft cage. It will have 3 or 4 females and one Male.

Shall I put in shelves or not and if so how high up the walls should they be? The roof is 6ft tall.

Disclaimer - I am aware of the risks and have plenty of other cages in case things don’t go to plan.

Thank you for reading.