We are thinking of changing our handling system so that it includes space for a holding pen with locking yolks to carry out TB testing etc. Is this a good idea? I know some people rave about yolks instead of a herringbone race - what do you do to get cows into them - put some feed down perhaps? Do you have them at wider spacing so you can get in between the cows for TB testing? Any design ideas that we need to think about or maybe don't do it!