Animals most definitely feel pain every bit as much as we do, but their reaction to pain is different. They are wired for survival, not whining for sympathy, they simply accept what is and move on. I wish humans were more able to do so...
I had a Narragansett tom who got hung up in the fence, it looked like he got knocked off the roost at night. I found him in the morning, hanging upside down with his shank in the wire. His leg was shattered.
I had to nip off the bone end with wire cutters, and placed a silicone blister bandage packed with neosporin on the broken end. After a few days, the marrow receded a bit, and I removed the silicone pad and applied surgical tape, gauze, and a wad of cotton batting as a cushion. For a few days he remained silently in the crate, and I figured he was done for. But the next day he was up, eating, and began to resent the cage. So I let him out on the lawn every day after the grass dried, and the flesh grew back over the end of the bone. After it was healed, he began to walk on the stump, and I made him a leather and wood prosthetic with a rubber pad on the bottom. He got back to mating the hens, and was the father of the Narragansett tom I just sold. He is the one who was mortally wounded by the Malamute attack, and having to put him down after all he'd been through was the hardest thing I've had to do as a poultry keeper.