They are very skinny for being seven. How much, how often, and of what are you feeding them?
Leopard geckos can never be housed together no matter the sex or how long they have been together. Eventually, you'll come in one day to a blood bath.
Sand or any other loose substrate should never be used in a leopard geckoes enclosure. No matter how long you've had it, it is a daily death threat. Switch it out for some non adhesive under counter lining. It is easy to clean, super cheep, comes in a variety of natural colors, and runs no risk of impaction. I get it at Walmart.
If that is one of your 3 main hides, switch it out for one that fully encloses the gecko. If that is one of its only choices it can become stressed from the exposure.