So my 7 month old Cochin just went broody. She's been sitting in the nesting box, this morning was day 3. She got up to eat this morning to eat something and I noticed there was no egg under her, so I put the ducks egg (that she had laid this morning and are fertilized) in the box to see if she would sit on it. I came back later today and sure enough she is sitting on the egg. My question is, can I take the ducks eggs that she lays every day and put them under the chicken? I've heard of some chickens sitting on duck eggs and hatching them. Is it too late in the season for them to hatch?