Hound? Collie? We've always wondered so any feedback would be helpful

This is Buddy. We’ve had him for over three years now, a stray we came across. He’s the sweetest, most gentle-tempered boy I’ve ever met. One of my two fur babies! We think he has some hound in him or perhaps Australian Sheppard mix, or if he has some collie in him somewhere. His fur is thicker, and sheds A LOT, and he has the most beautiful coloring to him. He’s got a very narrow chest and rib cage, not broad at all (Collie?) but has a very deep sounding bark. He weighs about 70 pounds now.

My husband and I always wondered what he had in him so I thought I’d ask you guys and see what you thought.