I have a local guy I use and buy in bulk, usually twice a year. If I can't get them from him I use Rodentpro and have always been satisfied with them. Even with the price of shipping it is much cheaper than buying them at a local pet store. Plus they don't have all the sizes I need. I have a chest freezer just for my rats.
You can try a different source at any time. If it has a great feed response it probably won't even notice.
5 day plan is fine and good.