What should I have done?

[MamaJohnson]

I have a darling cochin who sat on her eggs for 10 days (first time she has become broody, and I was so excited!!), but kept getting bullied off the nest by the other hens. So, one night I carefully moved her to an isolated nest. Come morning she got off those eggs and never sat back on them. I don't have an incubator (yet!), so we sadly lost 4 developing chicks.

Next time, should I do something different so she won't abandon the nest?

 

[Ridgerunner]

I'm not exactly sure of the procedure you used. Did you lock her in the new area so she could not go back to the old nest?

I'll give you a link to how someone else moves a broody. They claim 100% success rate but I'd be very cautious about leaving them in real tight quarters like that from a dehydration/heat viewpoint. If your area is cool enough and the outside box is big enough, well, it is your decision. I think the idea of the outside box is to keep her in total darkness.

How to move a broody hen
https://www.backyardchickens.com/forum/viewtopic.php?id=162759

With my set-up I don't have to move a broody. I can lock her in the nest and open an area for food, water, and poo with her staying on the same nest. Most people don't have that option.

There can be different reasons for moving a broody. For me what you were experiencing is the main reason. What I would recommend, if you can, is when you are sure a hen has gone broody, move her at night to a prepared area with a nest and a small area that you can feed and water her and leave some open area so she can go poo when she wants to. You'll probably wind up cleaning this area so you'll want access. Don't put the eggs you want her to hatch under her at this time. I suggest fake eggs, like golf balls or Easter eggs. Make the nest as dark and cozy as you can, with a nice, comforting, safe from predators look as you can manage. Lock her in this area so she cannot leave and the other hens cannot lay eggs in her new nest. If she stays broody for two days and nights, slip the eggs you want her to hatch under her at night and take away the fake eggs. I'd leave her locked in this area and the other hens locked out until the eggs hatch. There is always the chance she will stop being broody when you move her, so there is a risk in moving her. If you decide to move her and she already has started some eggs, you have to risk those eggs and move them with her. There are also risks in not moving her as you saw. Which way is the best is your decision.

Hope some of this helps and can apply to your conditions.