You have rabbit, a ferret, a gerbil, and a turtle how many different ways can you feed them?

Kevin has a rabbit, a ferret, a gerbil, and a turtle. He feeds them in a different order each day. In how many different orders can Kevin feed his pets?
4th grade math for my daughter and I know there has got to be some kind of simple equation or easy way to do this instead of writing them all out which I have been doing for a lot of the other ones and I know there is an easier way to explain it to her. Please let me know! I waited too long to ask so now it's past bettime!! :(

I would tell her to start out with 2 possibilities, then three and then four so she can see the effect of adding more possibilities.

There are 24 possible permutations of a 4 digit sequence. Where "R" = Rabbit, "G" = Gerbil etc:

RGFT
RGTF
RFGT
RFTG
RTGF
RTFG
GRFT
GRTF
GFRT
GFTR
GTRF
GTFR
FRGT
FRTG
FGRT
FGTR
FTRG
FTGR
TRGF
TRFG
TGRF
TGFR
TFRG
TFGR