switching to rats

at what age do most people switch from mice to rats? First time i tried it worked great, but then he stopped eating, and has gone back to only eating mice again :(
also apart from the difficulty of having to feed many mice when he's bigger, are there any real benefits to the snake for having rats in place of mice? I've heard that rats are more nutritious, but will he still be ok if he ends up with mice for ever?

It can eat mice for its entire life. Just a matter of how many you have to feed.

While the nutritional value is slightly different, the nutritional requirement of BP has never been studied.

There is no benefit except the convenience and price, gram per gram it's all the same.

Now the hard part is that not all BP will take multiple preys, so if your BP does not you may end up feeding it less than someone feeding rat.

If your BP accepts multiple preys you can feed the same amount of food and your BP will grow at the same rate, feeding will just take longer and get more expensive in many cases.

Ultimately feed what works.