Actually when I put her in the sling yesterday she took a while to get comfortable but then started to go to sleep in It! I will keep her in it longer today as you say and will observe and see if she is comfortable.She should have frequent breaks from the sling to rest and stretch if possible, but I would leave her in the sling for most of the daytime. A lot depends on your time and how she tolerates it. If she loves her sling, she could sleep in it, but it just seems to me that she might enjoy sleeping lying down some. That way she could stretch out legs and flap her wings. Bone broth from mutton or other meats probably would be very good to get vitamins and calcium into her. I am not an expert on chicken nutrition, since I use a complete commercial feed. Tuna and salmon can be used for extra protein, and liver is good as well.

For calcium I am getting her seashell grit as suggested by Saaniya and have also gotten calcium tonic for her. I also gave her eggsheels (I powdered them at home and mixed them in her food).