There are no remedies for internal laying, sadly. It's a hormonal imbalance and the only thing that could be done is a hysterectomy, not something I have money to do on several hens. With the two I have that are going downhill fast and the three I lost earlier this year from the same issue...
Yep, my blueberries are a hit here, too. I have one hen who I believe is dying from internal laying. She has no appetite, but if I even say the word "blueberries", she perks up and she'll eat those.
My splash Ameraucana, Snow, waits for my DH to pick her up in the morning when he lets them out, then in the afternoon when they go back inside. She waits at the gate, then when he comes in and says her name, she chatters in this tiny little girl voice and shifts from one foot to the other...