A good alternative to dandelion greens is dandelion root. You can usually find capsules at a WalMart, Target, or something like that, or even a health food store
, though more expensive. Just pop the capsule open and sprinkle some on their food, or on a little yogurt as a treat! I've used this to treat a chin who had been down with coccidiosis and after a month, he put on weight and was much healthier. BTW, though not clinically proven, the dandelion is not only a good source of vit C, but it supposedly cleanses/detoxifies the liver and helps the flow of gastric juices during digestion.
For those of us who can pick dandelion greens out of the yard, it is best to pick them BEFORE the flower opens. This presents the best source of nutrition. Once the flower has opened up, it saps the nutrients from the leaves and the root.