Ok I got a new horse and i've had him for a few weeks now. When I got him I was told he was unfit due to being out of work for about 8 months. He has to do quite a bit of walking or just a bit of trotting and he starts making noises when he breathes. It doesnt sound so much like he's out of breath but he kind of whistles. From what I know of he has only done barrel racing and he was sold to me because he wasnt fast enough. Im only using him for pleasure and riding lessons. He can go for a big canter in the paddock and be over the other side of the paddock (about 2-3 acres) and you can hear it clearly. When he starts this he doesnt even really break into a sweat like he's been working hard. So should I be worried, could there be something wrong with his lungs/breathing?