Well... you are REALLY going to have to seriously think this through. Having a large number of mice, or rats, will start to get VERY smelly... and to be perfectly honest, NO, it is NOT pure profit. You have to buy food, shavings, meds when needed, replacement bins, water bottles, ect.
I have a LOT of animals, and for me this is a full time job and is how I support myself. The smell, now that it is getting to be summer, can get bad if I am unable to keep my "cleaning" schedule. You also have to think about WHERE you plan to keep all these rodents, and whether your neighbours are going to complain. There is a HUGE difference in keeping a few bins of mice in your bedroom to feed your snakes and keeping several thousand rodents.
There is also the question of how you would plan to kill the animals when you have that many. Using a home made solution of Vinegar and Baking soda wouldn't be efficient or cheap when you plan to kill a large number of animals at one time. You will also have to invest in a freezer to store them.
I'm not trying to put you off... but I do want to make sure you are looking at this realistically and not thinking you can just jump right in and make tons of money right away. There are several feeder breeders on this forum, myself included, and I'm sure they will be glad to help you out with any questions or whatever.
Oh... and in response to your questions.... I use sterylite containers and have one male to four females and find that to be perfect. No over crowding and the male and females don't get "overworked." I personally prefer to use water bottles so if I need to administer medications or whatever I can simply add it to the drinking water without having to worry about whether the bin that NEEDS the meds are actually getting them or not. Others prefer to use a professional watering system. The automatic watering system does make things a LOT more easier to maintain. The water bottles do have to be checked on every couple of days. Generally when I clean the bins out, I give everyone fresh water.
Anyways.... good luck!!
Annie B. <:3 )~~