You have gotten your chicken coop and run built, and you have gotten your eggs hatched in the chicken incubator, and then you raised the chicks in a portable chicken coop, and now you need to start thinking about the hens laying boxes.
You are trying to determine the exact number of boxes you will require. There is no set formula you can use to tell how many hens laying boxes will be needed. Generally speaking the birds will fuss over one or two of the boxes rather than get into another box. they will literally line up waiting their turn, and squawking at the other bird.
One thing that you can be certain of is that the boxes that are the highest off the ground will be the ones the chickens use the most. they feel safer higher off the ground, so if you have a set of boxes with three on top, and three on bottom, they will avoid the three on bottom. Everybody wants to lay their eggs in the same hens laying boxes, and they will not be convinced to do otherwise.
When a hen is setting on eggs, the other hens will often stand on her back to lay their eggs if she is setting in one of the favored boxes. This is one reason why eggs do not all seem to hatch at the same time. a clutch of eggs is laid over a period of days, and then it may be added to after the nesting begins.
You should try to build a box for every two hens. that way if you have twelve hens, then you can figure on six boxes. your hens will not all lay their eggs at the same time, but having enough boxes will help you out if you have multiple hens trying to hatch eggs at the same time.
Remember that when your birds first begin to lay their eggs the eggs will be small in size. Do not assume that the size of your eggs will stay this small. they will begin to lay their full-sized eggs about the third or fourth time they lay. you should also note that when they are just starting to lay eggs they will not lay their eggs every day. Mature hens will lay an egg approximately once every eighteen hours. a new layer will often have days between her eggs, and as a hen starts to reach the age where she is getting to old to lay eggs, she will begin to lay less frequently. you can also note that a hen starts to lay smaller eggs when she is getting older also.