So first this is my 7 ~ Month old hen Britt; I've finally figured out how to maintain her at a healthy weight that allows her to 'fly' or at least jump the required height to move about her pen. Currently she is a clean bill of health I'm proud, and lucky to state! Sadly moving into summer I'm getting faintly concerned about these things; is there anything I can give her that will help her heart in the long run? I want to avoid anything that will intrude on her laying cycle; it's part of her daily routine that really makes her move to reach the nesting area, to lay and then to check on the egg (as well as habitually 'showing' me her newest egg when I bring the other hens feed) and thus keeps her active given she's never brooded on me before. Second; I recently got 10 Cornish Rock Chicks from tractor supply; I want to give them Vitamin D and anything else that will help their bones to withstand the body's rapid growth. While I do plan to monitor weight I just want to be safe with them given these are meant to be layers, with the exception of 1-2 for food and any roosters) in the future. What can I give them that's safe and won't endanger them? I've read that this type of thing can slow weight gain as well is that true?