"Disclaimer--- If your chucks fall over dead from the above printed words----- I do not know who I am and therefore will not be able to represent myself in a court of law" Not terribly encouraging 
My guys are house chucks. They're living in a 100 gallon. I pick various greens from the yard (mostly) and chop them up and mix them together in their bowl. This makes it difficult for them to be selective (don't want to put anything lethal in the mix), and Rigel seems like he'd be willing to eat just about anything (I don't trust him to know any better). Gracie is a dandelion flower addict (Rigel's a gentleman and lets her eat her fill of the dandelions before he moves in so I think that her diet is about 80% dandelions). Since Picris and Sonchus both have yellow ligulate asters for flowers, like dandelions, I was hoping to use these in an attempt to broaden Gracie's horizons. With her prediliction for dandelions, I do realize that her diet may not be balanced so I make sure that the dandelions are dusted.
I'll give the Sonchus, Erodium, and Malva a try and look for some more info on the Picris.
Thanks!
Alice