I'll add my WELCOME to Bert's! Glad to have you. A lot more information would help, although we don't require birth dates and Social Security numbers here......
In addition to Bert's questions, some idea of where you live would be helpful - just in general if you prefer - because that also dictates how you go about building your coop. Hot, humid climates year round pose different challenges than coops where we see hot, dry summers and cold dry winters.
How's the drainage around your proposed coop area, and do you plan to add a run?
What about predators? Do you know which ones are common to your area?
Lots of us stand ready to help and the more information you provide the better we can do that. You can click on the "My Coop" link under my avatar and see how we built ours, and there are lots of other wonderful coop ideas in the "Coops" section of the Learning Center. I must say, you are way smarter than I was when I started this venture - you're building and preparing first before getting the chicks. I did it the other way around and suddenly had 22 noisy, dusty, slightly smelly 5 week old chicks in my house with no place ready to put them!
So many questions before I can even start to make any recommendations or suggestions. Even then there are so many different ways you could go. We are all unique in climate, goals, locations, potential for facilities, and many other things there are no simple answers that cover us all. We all have our own way of doing things and within limits they can all work. Your challenge is finding ways people in your situation do things and try to adapt those to your unique situation. In some ways there are too many options. Anyway, welcome to the forum. You are in a good place to get opinions and answers. And it can be a great journey.
First, are there any restrictions based on where you live? Many towns, cities, HMO’s, and such either ban chickens entirely or put restrictions on them. Things like a maximum number of chickens, ban roosters, require certain distances between the chickens and property lines or buildings, not allow butchering, require neighbors’ approval, or require a minimum space per chicken. Even if you see neighbors with chickens don’t assume it’s legal. They may be flying under the radar or they may be grandfathered in.
What are your goals? Why do you want chickens? You mentioned learning experiences for kids and eggs. What kind of learning experiences? Taking care of animals either as pets or livestock, hatching and raising baby chicks, seeing the flock interact, learning where eggs and/or meat comes from, maybe even learning about genetics? Lots of possibilities.
How many eggs do you want? Egg laying has seasons. They normally lay really well in spring and summer and slack off in fall and winter, but there are techniques to get around that, at least to a certain degree.
Some people like to think there are magic numbers with chickens, square feet per chicken in the coop and run, length of roost space per chicken, hen to rooster ratio, brooder space, how high a fence has to be so they won’t fly over it, that a hen of a certain breed will lay a specific number of eggs per year, brooder temperature based on age of chicks, just magic numbers for practically everything. Real life doesn’t work that way. Each chicken is an individual with its own personality and each flock has its own dynamics. There are so many variables with any of this that there cannot be one specific number that works for all of us in all conditions. People with no experience have to start somewhere and the numbers given are often good guidelines for starting places. They will normally keep people out of trouble even if they mess up a bit.
But then you get conflicting guidelines. Some people say 8” per chicken on the roost is enough, others any you need 12”. I don’t say either. I say you need enough room they can spread their wings and fly up and down plus, if they need it, the weaker can get away from the bullies. For some people 9” is plenty, for some 12” is pushing it.
The biggest spread of magic numbers I’ve seen is in coop size. I’ve seen recommendations anywhere from 1 square foot per chicken to 20 square feet per chicken. Personally I’d never dream of one square foot, that’s just too tight for how we raise and keep them. There are a lot of variables in how much room a flock needs. One standard often repeated is 4 sq ft in the coop along with 10 sq ft in the run. If you have a flock of all mature hens that’s a pretty good starting point, but if you ever plan to add new chickens in the future or allow a broody hen to raise chicks with the flock, that’s pretty tight. You can follow the link in my signature to get my thoughts on space. It might answer some questions you didn’t know you have or raise some more. In general the more space I give them (coop or run size, roost space, nest size) the fewer behavioral problems I have to deal with, the more flexibility I have to deal with issues, and the less hard I have to work. But space can be expensive. You have to balance it.
I suggest you read topics of interest in the forum posts, look through the Learning Center at the top of this page, and start your own threads with specific questions putting specific information in your topic title so you attract the right people to answer your question. It really helps with a lot of these if you put your general location in your profile. That way we know your seasons based on whether you are north or south of the equator and maybe even an idea of your local climate.
I’ve probably made it sound a lot more complicated and harder than it has to be. Keeping any animal is a commitment but chickens don’t have to be hard. I applaud you for asking questions and trying to learn before you get chickens. Not everybody prepares the way they should. That’s a big reason you see a lot of threads with the word “Help” in the title. That’s often a lousy thread title by the way. If they include “help with what” they are much more likely to attract someone that can help them.
Welcome aboard! I'm brand new at this too and have my first flock on order - should be in around the first week of January or so. Everyone's questions are spot on so think those through first. I probably spent the better part of a year trying to define what I wanted and reading about chicken raising before I actually drew up plans and started building a coop. You probably don't have to spend that much time on it but in my case it usually takes a while for stuff to sink in. One thing I decided early on was I wanted to build the coop and run since everything I looked at commercially was way too small for the 20-25 birds I was planning on getting. In addition most coops and runs were very expensive for what you get. If you have some basic carpentry skills and a few good tools you can make a much better coop and run than anything you can buy in my opinion.
As far as how many, etc., that all depends on your goals, how many you're allowed assuming you're not living in an HOA or town with restrictions, and how much room you have. If you can manage it I'd think 3-4 would be the minimum since they're social animals and I'm guessing they do best with some company, but if all you can tend to is two that's far better than none. This is just my opinion of course but find out first if there's any restrictions in your area.
A few random pointers on building coops.
If possible it might be best to use an existing structure like an old play structure. This will give you a unique coop that is less expensive and a bit faster to build. Coop size depends on where you are located. For example if your area snows you would want to have more space for the birds in the coop. In contrast, if your weather is more temperate you can have less space. Lastly, go for functionality, so try to eliminate odd angles and make roost removable.