In my opinion on this topic, i would say yes there are lamping dogs that will kill fen hares and some that wont. But if you were into fen coursing what breed would you get for the job? I think most people would say a saluki X as thats what they are best at.
Sam as if you wanted a dog for lamping small fields what breed would you get?? proberly and whippet/greyhound cross, even though some salukis will be good lamping dogs they are not best sutied to the job.
I could go on forever, if your a shotting person and you want a dog to retrive phesants, what breed would you get? proberly a lab or