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.