I searched around here but I couldn't really find a thread (might have used the wrong terms) so here it goes.

I might get a problematic royal which only feeds on live. Considering how rats can pull up a fight I am thinking about using mice instead (he doesn't take freshly killed either).

Is there a good reason NOT to feed on mice ? Can I just feed two large instead of a weaner rat for example ? Do the rats have a certain nutrition value royals need ?