I've actually never heard of that either, and quite honestly I would never do that with my own. Possibly DavidReaves is correct? But what do I know as I'm still learning. Lol
I had the same issue for awhile. Come to find out, the reason none of my eggs were fertilized was due to my rooster. He was a year old and I NEVER saw him mounting a hen. I thought at that age he knew his job responsibilities. Apparently not. Lol. I started watching very close and nothing. Seven...