There's a problem with the theft of purebred poultry round here. That's why I have 2 big dogs!
The police seem clueless and were confused when someone's coop and 5 chickens were stolen (3 purebred and 2 ex-batt) and then a week later 2 chickens were returned (ex-batt). I mentioned to our rural bobby that it was probably to do with the breed and he said "no, they probably just felt guilty". It wasn't 'til I told him that some breeds are worth £50+ per bird that he took it on board. Still, too late now to follow that lead, they'll have been sold at market a long time ago!
He did however warn me that if I have a "Warning, Guard Dogs" sign up and then someone breaks in, gets bitten and then sues me, I'll be liable! He also told me that by taking that sign down and putting up a "Caution, pets running free" (or similar) sign instead, the dogs can do what the hell they like on my land and it serves them right for being on my property. As I've said before, nobody is ever going to just stumble onto my land, there are signs, 6 foot fences etc. etc.