I'm fairly new to this, but agree it is very breed dependent. I get most eggs from my hybrids which came from the egg farm ( an egg each most days, though not at the moment as it's been really hot). I've got one Orpington, she's only been laying about 6 weeks or so, I'd say I'm getting maybe 4 or 5 eggs a week from her which I think is quite good for an Orpington. Little eggs though!! I've got 3 bantams, the two hybrids and Rosie the Orpington and they give me 4 - 6 eggs a day at the moment. Though two of the bantams are looking after chicks just now so aren't on the layers pellets so they aren't laying as much as they would normally. Hope this helps
Plymouth Rock - Barred (AKA: Barred Rocks) have the reputation for being excellent layers. I only have one (so far) but she's not to point of lay yet. She's REALLY affectionate, as is my BO.
My BO is a good layer, too. The best layer I've got, however, is a black sex-link. My EE gives me a lovely green egg almost every day; usually I'll get six a week, sometimes 7.
I have 8 layers of all different breeds and I ALWAYS get 6 eggs a day, some days it's seven, once in a while I will get 8.
Keep in mind it takes just about 26 hours for the egg-laying process, so hens will lay just a little bit later every day, and when it gets quite late, they will skip at day. Then start the cycle early again.
I had some Buff Orps and just loved them. So good natured and calm. Their eggs were the same size as the other breeds I had, which included Light Brahmas, Barred Rocks, and some hybrids. I saw the buff orps in the nest boxes on most days and figured they each laid about 5 eggs per week. They are delightful birds. So much so, I named my two Honey and Peaches!
Between factors like illness, age, diet, broodiness, molting, all types of different stresses (for chickens) including weather patterns, and many other things that affect egg production, your daily total will vary like others have said. I have five 13-month old hens. My spreadsheet, started 3 months ago, says our flock's current 5-day running average is 3.8/day. But 5 weeks ago, we had a running average of as high as 4.6/day, and as low as 4/day. Those higher averages lasted for about 4 weeks. Now we're running closer to 3.4/day.
My most prolific producer has been the black australorp, who lays between .8 and 1 egg/day. The one who lays the least is the green egg layer, averaging .6/day. Then again, her shell takes a lot longer to make than the rest.
I have 5 hens of the breeds listed in my signature. I typically get at 30 eggs a week from them; this week was 3-5-5-5-2-5-4. I think the heat has affected them. So as long as you choose similar breeds, you certainly wouldn't need more than six chickens, and could probably get by with five.