If she’s growing normally on mice and rat pups as a 4 y/o then by all means keep feeding her mice and rat pups! Why would you want to pay more for feeders than you have to? I wish all my snakes would eat rat pups. I’d save some serious coin. If you really feel the need to give her larger prey then don’t feed her for 2-3 months and then offer a weaned or small rat. She may have a change of heart. 😀