How to prep soil for an orchard?

Hi everyone! I've been doing some light research on planting fruit trees. We have a small hill that is currently just a mix of grass, clover, and some bare dirt, that we'd like to make better use of!

Our entire property is pretty much clay so I know the soil could use some help. Where would be the best starting place? Lots of compost and top soil, ground cover, just let chickens run around there? Maybe all of the above haha? It will be winter/early spring before we get anything in the ground but we'd like to prepare now.

Your property sounds like it would benefit the trees to plant them with the Ellen White Method of planting trees:

https://permies.com/t/160325/Ellen-White-Method-tree-planting

To simplify this method, just do #5 by amending the holes with compost, peat moss, leaf mold, top soil and phosphate rock.  If you are against using peat moss then just leave that out.

Hannah,

Most fruit trees that we grow in such climates do not like clay in the soil. First they will grow, then develop problems and eventually will not be able to cope with that. It takes a few years to really realize it, so I would approach it very seriously.
Do you know what's the clay contents in your soil.
Do you know the profile of your soil - how deep the clay reaches?

Hi Hannah,  
We may be neighbors (Huntsville).  
I am growing numerous fruit trees on a slight slope that has clay about 6 to 10 inches of top soil on top.
After I cleared the area I put down 8 to 10 inches of wood chips to control weed growth and also put some biology into the soil.
I had access to all the wood chips I could handle and I have a small tractor so I could handle a lot.
After several years (started fall of 2020) I cleared up the decayed wood chips and put down various cover crops.  
Started with Winter Wheat and Barley over winter.  Was not a heavy producer but the roots help break up the clay.
This spring I put down some deer plot seed mix.
The deer plot cover crops I found at the local Farmer Coop have all that Dr. Redhawk recommended. Turnip, Tillage Radish, Rape Seed, Clovers....
I added more tillage radish and sweet Beets also.  I let these root vegetables rot in the ground in order to get more nutrients into the soil.
This will be my first real crop of Persimmons, Jujube, Goumi and Asian Pears.  Pawpaws take longer and I am only seeing a few of them.
Takes time but the trees I am growing seem to be robust and clay is not a show stopper.
My goal is to trap as much rain on this land as possible.

I have a food forest that has heavy clay as well.  I'm starting a Stefan Sobkowiak style orchard this year in another area of my land.  I don't do anything at all to the soil when I plant my fruit trees.  I have 40 or so right now, all are doing great.  I have cherry, apple, peach, apricot, pear, and persimmon, along with different berry bushes.  I plant in my native soil and then mulch heavily with wood chips around the trees after planting.  I would mulch at least 6 inches deep, deeper if possible, and then let nature do the work.