Hello! I just got three female rats last night, they were an rehome as the woman was moving. She was keeping them in a bird cage so I'm picking up a larger cage tonight. I want to litter train them so I should start that as soon as they move into the new cage? Is it too soon to move them to a new cage? They're using carefresh right now so I would use that in the litter box and something else for the rest of the cage?