Going to set myself up for breeding rats and probably going to start with 3 females and a male. I was wondering about tubs...

The 4 of them would need how much space (breeding tub)
What sized maternity tubs (assuming 1 rat/tub)
What size for how many rodents to keep feeders (until they are around 100g)

And would it be a bad idea to introduce the offspring from one female to the offspring from another (keeping all my feeders together based on sex)?