since your dogs are still alive then they must be cautious when catching. Some dogs will catch and release just to keep it stopped and bayed...and will get more catchy when you get there...these type of dogs will get careless when they are super fresh or in real tight quarters and on a big boar...I had some of these type just wondering if that is what you have...
x2 can your dogs hear u closing in on them or know your getting close? because if my dogs spot me its cause them to caught every time.. Too me, Sounds like you dogs are working as a team an getting the job done!! In bay pens the way they stop good dogs from catching is to dock teeth just a little... Not something I would do but it's your dogs..