I reckon it could be a boxer x greyhound..cause the boxer could give it the bob tail and longer face of the grey...he looks bob tail more than docked cause docked tail are usually more rounded at the end, bob tail looks more like a minature tail lol...so if its bob tail its probs got boxer, rottie, stumpy cattle type breed in it...jus my opinion tho, im not a pighunter (YET!)so a few of the blokes on here probs get sick of me but i have worked with alot of dfferent type of dogs as a dog handler at shows and protecion dogs.. but i am probably wrong cause i usually am haha...
Cheers, goose