Horned frogs have amazingly large stomachs for their size, a froglet just morphed from a tadpole is already large enough to eat large crickets, in some cases even pinky mice. I would remove the hind legs from the crickets though just as a precaution. Lucas in particular I would say is already ready to accept pinky mice. After all, I have seen much smaller Horned frogs eat pinkys with no problem.