This.  Get a soil test now.  Depending on where you are in the country, it is not too late to start, but you need to find out where you are starting out.

You get the containers from your county extension agent for agriculture, and fill them according to the directions, and take them to the agent's office, then in a couple of weeks you will know what you've got.

You need to know that first.  Then add amendments.  No two patches of soil are exactly the same so there is no way anybody can tell you what you've got, or how to make it "ready" for gardening without testing.

And the advice to start small is very good advice.  

If you've got something in that spot that will not allow it to be a good garden (houses contain a lot of different kinds of material.   Burning them deposits some of those things into the soil.  It's not likely, but you could have a spot that is just not going to work for a garden, and spending a little money on a small garden the first year will allow you to find that out without as big a loss.)

ALSO...if you have not gardened for a long time, or ever, you will find that a small garden is a lot easier to keep up and enjoy at first.  As the year moves forward, what looked doable in May will easily become unmanageable in July and August, and could make you hate gardening.

Start small.  You will be glad, and excited for your second year.

That's a really interesting plan, and it sounds like a good one.

If you care to share pics, and keep us informed of your "Chicken/Garden Crop Rotation" experiment, that would be awesome.

When you send in the test you will check the box for what you want to use that ground for....there will be choices like veggies, pasture, corn, soybeans, (or agronomic crops) lawn, etc.

You check veggies.

Then when the test comes back, it will show you the levels of certain essential plant nutrients, and will tell you how much per acre of fertilizer you need to add, and give you suggestions for how to add it.

For instance, it might say the soil is ph 5.5, in which case it may tell you to add a certain number of lbs per acre of lime to raise the ph to around 6.5 or something.

Or if you're deficient in nitrogen, it will tell you how much ammonium nitrate  you need to add per acre to bring it up to the level that is best for veggies.  Or it'll say use a balanced fertilizer like 10-10-10 at X lbs per square yard.

Normally it also breaks down the amount to apply to a number for smaller areas, like lbs per square foot or square yard.

What it will NOT do is give you a breakdown of the trace elements needed by plants (there are 16 essential elements), or, as someone above said, tell you if you have something unusual or toxic in the soil.  The chances of that are low, but if you follow the advice and end up having trouble, THEN you would need to look further.  Does that make sense?