JJ welcome to the forum and be prepared for a long wait before you find what you are looking for,,, as Malxwell says ,,,be prepared to visit many a farm to offer your services as vermin control, to hopefully " get your foot in the door" invest in a half way decent pcp air rifle and some kind of night vision as rat control inside buildings is a good way to get a start, also helps with pigeon control inside buildings
Good luck with your search
Cheers
Ray