You can offer it before they start lying they might Peck at it and Sample it but probably won't eat much but it's good to have so that right before they come in to lay they can eat some for calcium
You have a boy and the extra calcium can harm him in the long run. Definitely flock raiser and oyster shell. I feed this way and works very well, also if you have different ages at some point or hens go out of lay this is better. @U_Stormcrow knows alot about feeding