I'm sure there are a lot of people interested..... and good luck.
I have a few friends(Scarborough) that have the same problem as I do with the current rat breeders we use.
Reliability !! Orders either don't get delivered on time or it's never a good time to pick-up the order.
Our last order was 6 weeks late, so we had to resort to pet store prices.
Another supplier we use has no clue on size...ships smalls for mediums or weaned for smalls,etc.
If your prices can be competitive and you can be reliable, you'll do great... word will spread how good you are.
Everyone knows someone and you'll have business coming out of your.....
Message me when you get started, I'd be interested.