Welcome! First thing is, many tubes that are advertised for six chickens really aren't big enough for six. They are usually big enough for two maybe. So what kind of coop did you get?
Are the chickens going to be in a run or free range in the yard? Is your main priority egg production? Meaning you will get new chickens every couple years to keep the production high? Or are you more interested in pets that happened to lay eggs?
Leghorns are known to lay the most eggs but they can be a little flighty. But there are many dual purpose breeds that would be great for you. Such as Rhode Island red, silver laced wyandottes, Plymouth rocks,australorp, easter Eggers. Google the Henderson chicken breed chart, it gives you a good outline of different breeds, cold heartedness, egg production etc.
This is similar to mine...don't forget that chickens need to 2 to 4 square feet per bird inside space and 10 square feet per bird outside space when confined.
Everyone is right on the money about the commercial coops. None of them are anywhere near big enough for what they advertise. Bauerdog's coop is right nice and would work good but if you're not as handy a carpenter there are a lot simpler setups you can build for a reasonable price. I don't know if you've looked in the coop section here on this site yet but there are tons of homemade coops there that you can get ideas from. When I was starting out I was hoping to find a commercial coop that was well built and big enough but I couldn't find anything so I opted to get a book on sheds to learn the basic framing and build my own. Man I'm glad I did too - I ended up with a way better coop with attached run to house 25 birds for around a grand. That doesn't mean that's best for everyone's situation but my point is you can build what you want and need for a lot less than you'd think in most cases and you don't have to be an expert to build a nice setup. Just something to think about down the road.
