What does that mean "can't leave the bowl?" Are you saying she is constantly eating? What is her current diet? Chinchillas should eat many times during the day to stay healthy. I've observed with mine about every two to three hours. An average sized healthy chinchilla will consume about two tablespoons of pellets and a small handful of hay in a days time.
I recommend pelleted diet that is alfalfa based while feeding them fresh loose timothy hay, keeping both in constant supply each day. Food mixed with seeds or treats is an inappropriate diet that will cause health problems over time that can be quite serious.
Also things like dandelions should be treats that are on occasion, no more than the equivalent mass of two raisins per day. Chinchillas do not need anything other than hay and pellets to stay healthy and will be healthier on a restricted diet.
As far as I know chinchilla feces are supposed to come out black and mostly dry. If they are green, sticky, or stain the shelves that is a sign food is not being digested and can indicate stress, parasitic infection, or an improper diet.
I've observed this myself.
You say you want them to be much healthier. What makes you think they are in poor health?