I will try to answer this and why somethings are that way
About greens: Greens are rich in Calcium (thats good), but some are also very high in phosphorus (not good) with others being high oxalates (not good-binds calcium)
So you want to balance those foods using the good calcium - ph ratio foods as staples, the ones with higher ratios as occassional and the ones that are very high in Ph and oxalatic acids as rarely.
As with most foods, some that have undesirable properties, often having someone that is very desirable that others lack. take kale as an example, the calcium : ph ration is not that good, but it contains many things that are good, like antioxidents, so you would use it as a rarely or small amt food item, mixed in with good ones, like collards, dandelions and mustard greens as staples.
Below is a link to a greens chart with photo's of the greens and common name they are know as around the world, marked as staples, occassional and rare. Those markings are based on their Ca : ph ratio, amount of oxalates and nutritions value.
Lettuce such as bibbs, icebergs etc are mostly water, little nutrition.... so not normally a good food item, BUT, for a dehydrated dragon, this is something that is good, it gets fluids back into them quickly so you would not want to fed it as a staple mostly, but at times it may be the best food for them, ie, when they are on sick, taking meds or dehydrated.
Same with the veggies, some are high in nutrition, but are higher in other things that you want to limit. Given occassional with other staples is okay, but not as a staple.
As for feeders, that depends on age and nutrition also. We would not feed superworms to young dragons due to the chitin shelling that does not break down good in a young digestive tract or a baby that has reached a certain weight so it can process that food, but right size crickets have less and softer shelling, so are safe for all ages.
Mealworms can be fed also after they are old enough(too young they can impact a small dragon) but superworms are a better meat to chitin ratio food.... so more perferred due toi nutritonal content and less risk. We do not feed mealworms to anything, but do feed supersworms to subadults and adults.
Sikworms are an excellent choice for all ages, they are soft bodied, great nutritional value and they have the added benefit of containing an enzyme called serrapeptase, this has properties that make calcium absorption more efficient, can reduce inflammation, pain and best of all it can break down arterial plaque. It's acts as a cleaning agent for the vascular system, can lower blood sugar levels (these tend to run high in captive breed bearded dragons) and very beneficial in older dragons. Yet too much of a good thing can be harmful too
The best diet that we know of so far for bearded dragons is a varied diet of lower fats, good calciums, lower phosphorus, low oxalates and occassional other foods that may have some of those in higher amounts. Using the higher ones in small amounts is not a problem if mixed in with the staple ones
Hope this answers some questions you had
Edible greens for bearded dragons
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