I think it depends on the chicken, I know that sounds odd but I have some really old hens that have NEVER gone broody and some hens that I continuously have broody issues with (won't stop). If you have a hen that has a tendency to go broody, I just let the pile grow and she will naturally want to sit after her egg cycle is finished. If you do this, try to mark the eggs that are the newest so you can get rid of the old, saving space for the good ones. I mark mine with a pencil with the date layed.

First things to think of is are any of the hen breeds likely to go broody. Alot of breeds have been bred specifically not to go broody, so find out if any of the chicken breeds you have could go broody.

Is your rooster of the same breed? If not try to find out what your chicks will be if they will be a crossbreed. You need to consider if the chicks will be any good as layers or for meat and if not are you prepared to keep them or cull them because no-one may want the crossbreed you have bred?

Your chickens will also be 50/50 hens and cockerels. What will you do with the cockerels. I don't want to sound really negative, but these are things you need to be aware of before you start.

I am experimenting with some ameraucanas hybrids which I am hoping will have the coloured eggs but lay more eggs. It may work or I may have 50+ chicks that don't lay and don't have the blue egg gene.

You don't need to keep the eggs for them to make them broody. Afterall there will be eggs every day. You just need to watch for signs that they are going broody. It's hard to describe what they do, other than to say they tend to fluff up their feathers, look and walk differently and are reluctant to leave the nest box. If you are watching them every day you will see when one begins to act differently. Any chicken that has the potential to go broody could start anytime from now. I have a welsummer who is showing signs of going broody (and I don't think they are supposed to!).

If you have specific eggs you want the hen to hatch you can keep them for up to a couple of weeks and they will still have a good chance of hatching. But you will need to put them in an egg box and turn them (top to tail) at least once a day otherwise the embryo will stick to the side of the shell (that is why hens continually turn their eggs). If you turn the eggs you can put them under a broody hen even if they are a couple of weeks old.

Ideally a broody hen needs a place away from other laying hens as they may force her off the nest. I have been told it is best to move a hen at night to a new private hest box and put her with all the eggs that you want her to hatch. Make sure she has a daily supply of food and water next to her as she will not want to leave the nest box. The rest is up to instinct really. Good luck.