If the dandelions are from your yard and you know what has been used on it.No pesticides, fertilizers, weed killers etc.They should be fine to use.I know my yard is safe because I have a couple pet chickens that forage.So I dont use anything and even if the neighbors may frown on my weedy lawn I dont care.
I also have mulberry leaves and plantain(a small edible weed) and some planted stuff like arugula and parsley. All of it is better then anything you can buy at a store.Store bought is old,most the nutrients are shot, they use pesticides on it and sometimes it can have Salmonella..So the possibility of a little doggie pee that can be washed off is worth the risk to me to feed fresh picked greens to my animals( the beardie and my birds and the occasional green that my chameleon might eat).As well as for the feeder insects.
So there is my little piece of newbie advice....But id worry they arent eating insects,that is more important right now.