Live should be a last resort. I have yet to meet a Royal that cannot be converted to F/T and I have seen a few F/T eaters that refuse to deal with a live rat. (I have rescued out close to a 1000 royals now) and every now and again one comes back because it will not eat. In the three cases now the F/T eater was offered live and refused it. The three cases all ate with no problems once back in the facility and offered F/T again.

My point is Royals often imprint on food. An adult mouser has to be struggled with to convert it to rats and often will revert back to mice given a chance.

I would offer what you have always offered not try something new. A regularly eating snake often will not eat new things. Routine is a trait of these animals.

There is a caveat here, if the you know the snake was started on mice a mouse scented rat may help, if that fails a mouse may work but you might get stuck feeding mice and mousers often are under weight because it just isn't big enough when they are still in a growth spirt, they will fill out sooner or later but IMO it is a poor food for a growing snake and a inappropriate food for an adult.

Live feeders often can be a pain to switch, it isn't a huge problem feeding live as long as it is supervised, but that takes time an extra 10 or 15 min per snake and if you care for any number that is potentially a lot of time. It is such a fluke for a snake to be injured by dead prey it is almost funny. It however is not uncommon for a snake to be hurt by a rodent defending its life.