I’ve tried leaving fake eggs (golf balls) in a nest several times, increasing them one a day until I have over a dozen, then just leaving them for a few weeks. I’ve done the same with regular eggs, marking them so I know which ones are to be left. One time I got a broody hen when I did that, but she went broody in a different nest. I don’t think that counts.
I leave one golf ball in the nests at all times and collect all the eggs daily. My hens go broody on that one golf ball, and they are not Silkies. When I was growing up on the farm we collected all the eggs every day and did not use any fake eggs. Hens went broody anyway. When the broody hormones hit, they are going to go broody. Until the hormones hit they won’t. I don’t know what causes the hormones to hit, but it is not a requirement for the eggs to build up in the nest. That much I am sure of.
I leave one golf ball in the nests at all times and collect all the eggs daily. My hens go broody on that one golf ball, and they are not Silkies. When I was growing up on the farm we collected all the eggs every day and did not use any fake eggs. Hens went broody anyway. When the broody hormones hit, they are going to go broody. Until the hormones hit they won’t. I don’t know what causes the hormones to hit, but it is not a requirement for the eggs to build up in the nest. That much I am sure of.