Depends, do you have cattle or bison being kept there? If so I would add a hinge. One of my sisters had bison for awhile. The bull got a leg thru the gate somehow and tore it off the hinges. I told her and her husband it was not strong enough but they thought they knew what they were doing.These are the hinges I’m using. They are rated at 900 lbs per pair. The gates will probably weigh 150 each at the most.
They are a cool design and ride on a large ball bearing.
Still think three are needed?
https://www.progatesupply.com/collections/hinges/products/7-barrel-hinge
View attachment 290395