Picky pigs

I was not expecting to get my guinea pigs, they were freecycled (!) and so have not grown things with their winter welfare in mind.
I have been giving them various herbs to see what they like and so far they have eaten Good King Henry, Sweet Cicely, Mint, Sage, Fennel, Parsley, Wild strawberry leaves and even snippets of Rosemary with gusto. However they completely turned their noses up at Tarragon!
They like Valerian too but I am wary of giving them too much in case it has Peter Rabbit type soporific effects.
Has anyone got any ideas for winter greens I can grow for them?

 

Well done Liz for taking them on - youre a star

This seems to be a good site - I have rabbits but I know GPs are different in their needs

http://www.guinealynx.info/

 

We used to get all sorts of green stuff from our local Asian shop years ago - mostly cabbage, lettuce, sprouts, and carrots.

I seem to remember they liked groundsel too.....

 

My vet used to say that carrot tops were not good for guinea pigs. I haven't had any to look after for years and don't know if this still holds good as something not to give them.