I didn't see the moorhen as too lowly to hunt, In fact I enjoyed many a hunt with my Harris on them....up & down tree lined ditches, them seemingly disappear into thin air! But I ended up with a wet, muddy hawk on many occasion, sometimes cutting short a mornings sport, plus my male was mad for them & like your female on rats would ignore everything else around when there was a hint of one around. So when I got the goshawk, I decided they just weren't gonna be on the menu if I could help it :-)
The main thing is, if you enjoy what you're doing, stick at it!