Ball bearings falling out?

2005 Prius with 255,000 miles. I've found these 3 ball bearings in my driveway over the past couple of weeks. Note that one is larger than the other two.

My driveway is about 800 feet long, with a 90 degree turn half way, near where I've found the bearings. The driveway surface is asphalt, 40 years old, well worn, lots of cracks. So all three could've fallen there at the same time, but I just didn't see them at first.

I jacked up each corner of the car. Didn't feel any play in the wheels, so I don't think they're from the wheel bearings. Also, the CV joint boots seem to be intact. No unusual noises suggesting wheel bearing or CV joint issues.

I suspect they came from a delivery vehicle, but does anyone know where they might have come from on my Prius? Car still runs great, but the high mileage makes me a bit nervous at times.

 

Could be. Not from my house, but the area is 400 feet from the house, so things can occur there that escape my attention. (I live in a rural area.) Thank you for taking the time to help ease my concerns. Much appreciated!