I hate it when they do that! but they do!! This is not uncommon with young egg layers. Your set up sounds fine, except it is larger and higher than the one I use. Covering sides of the tank could work, I would suggest adding paper towel tubes as hides. (disposable!) You also may want to add another egg box. If she is the youngest, the other 2 may be dominant. It is also possible, as you mentioned that the eggs aren't good. Try incubating/candling them. Take heart, as the issue may resolve itself as she gets the hang of it!
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