So with 19 girls you'll probably see between 5 and 15+ a day (maybe a few 19 days here or there). I know that's a pretty big range but I have 12 (6 over a year, 4 are 22 weeks and 2 are 17 weeks. 10 confirmed eggs 1 I'm certain is laying but haven't confirmed her egg yet. Of the first 6 I would get usually between 2 and 5, but since the younger 6 started I get between 3 and 6 right now but that's with the heat too. I would guess with good circumstances and no broody you'll probably average over 12 a day though.
Red combs usually means they are or are close to laying, but don't let that fool you. I had one red for almost 4 months before she gave me an egg (she was 9 months old for her first lay). Yet I have another that my friend and I actually watched lay her first and here almost 2 weeks later she still has a small pale comb. So yes you may have some start soon but there is not real time line for it.
Selling eggs... I don't, at least not yet. I do however supply my parents about a dozen every 2 weeks, and one neighbor when I'm in surplus because my chickens are on the side of the yard closest to his house and I have had a few escape to his yard. So that's more of a good neighbor gift. Obviously you need to wait till most of your girls are laying to see how much you get vs how much you need. With my 6 I did have a few weeks early on in was getting between 2 1/2 and 3 dozen a week. Sometimes we go through that much some times we don't. For a family of 5 we use to buy the 5 dozen at Costco every 2 weeks.
Once the younger 6 actually get regular and the Temps cool down I'm sure I'll get 6-12 eggs a day and then will certainly have to consider selling some, but hey friends and neighbors right...
