I've been reading up about wing flipping in Electus since one of my friends thought that his Electus had that problem. In the process I found some interesting articles.
I read that over supplementing their food can cause it because they live of a low nutritional diet in the wild. They mainly eat fruit and veggies and when they are given a lot of pellets and/or extra vitamin supplements are added then it can cause the syndrome. They also develop allergies when given the same type of food all the time, for example the pellets, allergies also cause wing flipping.
If there is Vit D3, spirulina and/ or vitamin A in the pellets then it can cause wing flipping .
I read that they need a high Vitamin A and Calcium diet. Pumpkin and seeds, carrots, broccoli leaves, dark green vegetables and dark orange or red fruit & veg are high in Vitamin A. If there is vitamin A in the pellets then it can mean that he is being over supplemented. They have the capability to eliminate excess vit. A in its natural form but they can not eliminate vitamin A in the form of an unnatural supplement (like pellets).
Calcium deficiency can also cause wing flipping. Food high in calcium are collard greens, mustard greens, turnip greens, dandelion and watercress.
Although the first article is about toetapping it addresses pellets.
toetapping
diets