I've been on big organised coursing days ,,with lurchers bred out of the top lines,,and herd them let out the odd yip and yap,,,yet them dogs still killed hares,,,and of course there owners kept them...
The worse thing is not catching game,,,if they yap the odd time but catch plenty,,so what,,,if they don't catch any,,,there's your real problem..
Ask yourself can you live with it