Silkies are known to go broody a lot. That does not mean every Silkie will go broody a lot, it means some go broody a lot. Some will never go broody. You have three. I don't know if any one of yours will never go broody or will go broody tomorrow. With living animals you just don't know.Ok.. so I'm clearly new to this chicken world, so please bear with me!
I have 3 silkie girls who are all laying regularly. I've never had a broody episode that I've heard others talk about. Mine just lay their eggs and leave the coop. So how does this work if I want them to hatch the eggs? If I just don't collect the eggs will the naturally do it, or does it just not work like that?!
Three different times I added one fake egg a day to a nest. I used golf balls. I let the number gradually get up to 12 and them left them there another two weeks. My hens do go broody. One time I did that I had a hen go broody, but that was on a different nest. I don't think that counts.
One time when I was away my chicken sitter did not collect the eggs. When I got back 4 days later the eggs had piled up and I found 2 hens on two different nests. I got back after dark so I took all the eggs away so I could start fresh. There was only one golf ball in either nest. The nest morning no hens were acting broody. If I had left the eggs on the nests another few days would one of them or both switched to full broody mode? I'll never know. I do know that neither one was fully broody when I removed the eggs.
What I take from this is that you cannot make a hen go broody by letting the eggs pile up. You might be able to influence one to go broody if she is leaning that way to start with, but if one does go broody it may just be coincidence. I find the method extremely unreliable.
I personally don't like to leave real eggs in the coop overnight, it might attract egg eating predators. But if a hen is broody she gets eggs. The only time I've had a snake eat eggs out from under a broody hen was in the middle of the day.
Where are you located? Are you north or south of the equator? Hens go broody a lot more in summer than winter. And I also wonder how old they are. Some will go broody their pullet year but most tend to wait until they are a year old or older.
I see nothing wrong with letting eggs pile up to try to influence one to go broody. Mark them so you know which ones they are. If you do get a broody, collect the eggs you want her to hatch, mark them, and toss the old ones. If you want, we can discuss what to do if you do get a broody.
If you do try it, let us know how it works out either way. And good luck.