The lighter breeds are definately good flyers and they can be excellent flyers if they free range and practice at it or find the need to fly. When I lived in Illinois I lived on 40 acres and left the chickens free range all the time. I soon found out that heavy weight breeds were just not going to make it on my place and thought I was going to have to go to a pen system as the critters were thick.
I knew a fellow chicken guy in the next town over and he told me to go with the light breeds so I had leghorn, lakenvelker, andulasian and minorca, egyptian, etc. families, that when raised in a free range environment that they do quite well. So I did, I did have a loss or two each month but not like the slaughter of the heavy breeds.
These birds would range in the field behind my house and when one spotted a predator it was nothing to see them fly 20, 30 yards or more (especially if the wind was at their backs) to the safety of the barnyard and then a lot of time to the top of one of the five out buildings. They sort of flew like wild pheasant they would take off flapping their wings really hard, then sail for several feet, flap real hard, sail and so on to the point they wanted to go.
The best chicken flyers I ever saw were the barnyard banties we had around our farm growing up, now they could fly like pheasants.
Yes, if you really want to see how far a particular chicken can fly introduce them to snow.
