My experience on mixing birds is that younger ones adjust to each other better.
Do it gradually- as you are.
My experience is with deep straw in nest boxes. I love to reuse it on the garden.
I have seen sand used. It has to be coarse or at least medium grain to avoid inhalation I have read...
Kerry, we totally relate to your obsession! I had 6 kids and the youngest is now 12. Hence new baby chicks fill that gap. You sound like you are doing a great job! I would watch your dogs though as it sounds like they weren’t brought up with the chicks. If they can find a way to conquer and...