But for back yard egg flocks, at least until something poses a problem, there's nothing on the books at all, and the city actually wants to encourage more of this sort of thing.
It's my understanding that Chicago flat out forbids raising for slaughter and slaughter, so for those into eggs it might not be a problem but does prevent those that want to raise meat birds legally...
Storage, pricing, packaging, customer service, issues that "nobody thinks of in advance," the sort of things any small business needs to keep in mind.
Get a second fridge (even a small apartment one) and if possible put it close to your door or in the garage if that works... When dealing with the pubic you are going to have some people that insist on 'looking' over your eggs and picking the dozen they want, or worse... Having a separate fridge gives you this ability without further conflict or having to invite people into your kitchen... And regardless of them not needing refrigeration in the US it's pretty much a given to the public that they should be refrigerated...
Date collection times on the carton, if you want use a coded date, this way you can monitor their age and provide a specific day to the customer when they ask, and some will, or worse, just wait until someone shows up with a glass of water to test your eggs for freshness...
As for pricing you won't make any real money, but you can pay for the feed... I like to get $5 per dozen but generally take $4 plus a carton in return... If people gripe over the $3 or $4 you want to charge point them towards the nearest grocery store and tell them they sell theirs cheaper and you won't feel bad if they go there instead...
Egg cartons cost upwards of 50¢ make sure you have this factored in...
Customer service is always tricky, may I suggest you print up a page that explains the differences between 'fresh' eggs and commercial eggs... Make sure that paper touches upon cleaned and sanitized eggs and your fresh natural eggs... Also very important make sure they are aware of 'blood spots' the public has become so sanitized to natural that most will freak out when they encounter a blood spot...
Now you of course live in the city where it's different from the burbs, but I have seen many small egg farms with a fridge outside (under a roof or what not) and they let their normal buyers just swing by and get their own eggs and just slip the money into a slotted lock box... Saves a lot of hassle...
Anyway way good luck on your venture...