I started shooting over my Lab at the same age, the trick is short trips of an hour or 2 max, make it a training session but make it fun, i had her hunting up rabbits, but also taking Crows and Pigeons if we came across them but i think sitting waiting in a hide or even roost shooting will be a bit much to ask at this age.
The other thing is i would only shoot 1 or 2 rabbits as well, get some good hunting, control work and retrieves in then call it a day and dont fire to many shots over her, 3 or 4 over the space of an hour or so Max.
Good luck mate.
Dave.