Hi Saveria - thank you for the welcome. It's common around here for neighbors/friends/relatives to swap eggs. He also did have lots of chickens of various breeds.
I recently got this mixed breed hen from someone who couldn't give me any details about its parents, but who also raised Australorp chickens among other breeds. The big, floppy comb & the almost daily laying of big, white eggs makes me think Leghorn; the color is suggestive of Pearl Star Leghorn...