"Hello Mr. Farmer. I see you've got plenty of rabbits on.
Do you want to keep them all?"
OR
" Do you have anyone doing your rabbit control, if not, I'd be happy to help, for FREE"
Farmers love that word LOL.
Obviously stating that you have 100% respect for livestock, neighbours, fences etc etc etc.
Also you'll keep an eye out for any undesirables.
Shit I've said too much already, took me nigh on 35 years to get my patter right but it works as I've got more permission
in the last 5 or 6 years than I've ever had in my life!
Cheers, D.