My EE's have all tended to be late bloomers in terms of laying....although they grow probably faster than any other chicken I have had. I have never had orps so not sure. Daph or Terry could probably tell you if they are generally late as well. I do know that since that heat wave the end of June we had, all my girls have slowed way down and I can not seem to find any good reason at all. It is so bad that I am going to have to get a few production breeds just so we can eat eggs.
As far as ACV; some believe in it and some don't. Even hundreds of years ago people knew of the mild antiseptic value for it and the fact that it flushes the kidneys and prevents kidney stones. Someplace along the line farmers started to add a little to their chickens water as a general health tonic and probably they figured it might help respiratory infections. There have been a lot of controlled studies with it. Some say it works miracles and some don't see a huge difference, so those really have not helped that much either. As long as you don't overdo it on how much you give though you really can not do any harm. If they (or us for that matter) get enough to lower our bodies PH too much, then it can cause some problems....but that is with anything good for you, too much is usually bad news. Here is one of the articles that explains some more
http://poultrykeeper.com/health-suppliments/apple-cider-vinegar
That article is from the UK. They have done a lot more research on ACV. That dose they talk about converts to 2.5 oz of ACV per gallon of water. But that is for a week per month and not every day. The most accepted dose here to use it all the time is
no more than 2 tablespoons per gallon (one oz per gallon).