by nature Greyhound, lurchers run after small animals ie a rabbit so maybe it could be wise not to let your guineas run about near them if you do get one, I think I personally would be a bit dubious but also know they are such loving breeds, a neighbour once had one called Beau she was so sweet but was so daft she broke her leg bouncing about, she recovered I might add,
I have a whippet and he is fine but obviously you have to be sensible. I wouldn't trust him at all alone with them lol. He goes up to them in their run and they have grown up with him so they're used to him and then they chew his nails and he's not bothered seeing them in their cage, but it's just the erratic movements...I'm afraid hounds are just programmed to attack. But if you're sensible about it then anything's possible!