The prey drive in the combination of greyhoundxbull must be the highest there is in a dog, and i know/knew a fair few who swear by them and seeing some work i dont disagree, having said that ive had whippets and colliexs that took fox, and a grey/colxsal/grey that loved fox above all else. some dogs wont ever, some jib, mine where never overmatched and not started young so they did ok. The comment about has to have bull in was either a wind up or some 5 minute country man so i wouldnt let it bother you. some cracking dogs on this thread by the way