How long do dumbo rats grow?

Dumbo rats usually grow when fed just like everything els but dont force feed or over feed it if you want it to be bigger thatn your hand your gonna have to wait a while wich i mean 1 month or so because they become adults within 5-6 weeks i curently have one rat that is a dumbo and she is still a baby but shes really smart she knows me and my scent and can do two tricks stand and spin