What is a normal/healthy level of iron that I should see in my lab analysis?
Caveat, I am no expert.
As for healthy, I think it depends on the copper and zinc levels. That is why I send my results to an equine nutritionist for balancing.
As for normal, Dairy One has compiled years of results into a library of averge results by forage type, state and season.
I almost guarantee what you see will be too high 
What then really matters is the copper and zinc level.
What does your report say?
Iron (ppm) 667.44 (dry basis)
zinc (ppm) 21.93
copper (ppm) 5.46
So yes, as expected, Fe is quite high. But worse, Cu and Zn are low, and the ratios very off.
You want the fe:zn:cu ratio to be in the 4-10:1:3 range. If you have a manganese reading, that’s 4-10:1:3:3.
The 4 parts Fe is better, but if you can at least get it down below 10, that’s fine.
Since you can’t lower the Fe, all you can so is increase the Cu and Zn. I do that by adding polysaccharide copper, and p. zinc, from either Uckele or Horsetech. I think California Trace also has those.
thank you for your advice.
one more question: could the iron be high because the hay was treated with propionic acid used to cure the hay in a wet hay curing season?
Just adding that it might be worth retesting. Iron here is always high, but last year was really high. Someone suggested retesting. I did and it was about half. Ask your feed store, they should know what is normal for your area.
