The key word is that it “can” hurt their internal organs, not that it absolutely “will”. All the studies I’ve seen have used Layer feed either from hatch or starting at 5 weeks and those chicks get nothing but Layer. I have not seen any studies that show when they can handle the extra calcium in Layer.
It’s not about how much is in one bite either, it’s how much total calcium they eat in a day and that for several days in a row. If you feed them many treats or if they forage for much of their food the amount of calcium in Layer is less likely to harm them because they are not eating that many grams of calcium.
No one can tell you if you have or have not harmed them. Even if you have that damage may be minimal. What’s done is done. You can’t change that. While they should be able to handle that amount of calcium at 19 weeks you might want to feed them a lower calcium feed until they start to lay. It won’t hurt and might possibly help.
Since I usually have a mixed age flock about all the time I never feed Layer. I feed a low calcium feed and offer oyster shell on the side. The ones that need the extra calcium for the egg shells seem to know to eat it and the ones that don’t need it don’t eat enough to harm themselves.
I know it doesn’t help but don’t beat yourself up too much about this. You are not the first one to do it and usually it works out OK.
