Leash for male boxer dog

Question
Which do you recommend for a BIGGGG male Boxer dog and myself .  Harness or gentle leader?  I have been told given the shape of their snout and breathing the harness is better and which I presently use.
When tired or just being stubborn he just lays down in the ditch as he does not like it. I just wait and he eventually gets up.

When not walking he has a lot of freedom as our property is very big.

Answer
First of all, leash training should start as a puppy.

Secondly, you cannot muzzle and harness a Boxer because they are brachycephalic like bulldogs, etc.. which are the short-nosed breeds. For this reason, they cannot wear the typical muzzle or harness.

You can use a good, thick leash and a wide collar for a Boxer. If you choose a harness, it needs to be made for a Boxer breed. Go to: http://www.boxer-dog-breed-store.com/index.php?main_page=index&cPath=4

Your Boxer is accustomed to roaming freely on your large property so leashing and harnessing him is not normal for him. If you had trained him on a leash at a young age, it wouldn't bother him at all.

Now, you must train him on a leash or with a harness and leash.

Buy a harness and leash made for Boxers and use it in training on your property as often as possible. Your property is safe and secure for him so his training will be more successful. Reward him after each training and during training when he does well.