Right after baby birds fledge, they're unable to fly very strongly...sometimes they can only hop around. It takes a few days for them to strengthen their wings and get the hang of flying and avoiding predators--it's a very dangerous few days for them. Normally, the adults will try to get the babies to follow them to some sort of cover, but if they're in the backyard, dogs can be a danger. I always keep close watch on our yard and any nests I know of to make sure I don't accidentally sacrifice any youngsters to the dogs
Right now we have a robin nesting in the side yard. The eggs should be about at the hatching stage, so in about two weeks, I'll have to be very careful about searching for robin fledglings...
Although it's worrisome to see them in the middle of the yard or on the road, it probably means that this has been a good hatch year! The more chicks fledged, the more likely you are to see them.
But holy catz! It sounds like you're way ahead of us!! We've been extremely cool for this time of year and all our nesting has been delayed.