Individually. Every dog I have ever met loved chasing deer, running deerdogs paired up makes for the type of useless arse-biting 'haunchers' often pictured here. A good dog strikes the front end, running a pup paired-up teaches it to go for the haunches and will ruin it as a deer dog.
guess you not got bull xs then mate ?
I wouldn't have one as a gift.
you dont need bullx to kill deer mate