I feed my piggies veggies once a day in the evening. They get one cup of vegetables per day. If possible it is better to split their veggies into two feedings (i.e. 1/2 cup in the morning and 1/2 cup in the evening), however I'm usually rushed for time in the morning so I can only manage one feeding.
Below is an idea of what I feed each pig on a typical day.
Daily staples:
2 large lettuce leaves - from two different varieties (eg. cos and red leaf, green leaf and butterhead).
2 sprigs of coriander
1/8th of a bell pepper
Then I choose one thing from the following list to add to the above and rotate it each day:
Small chunk of zuchini
2 cherry tomatoes
1 baby carrot
Small chunk of celery
Small chunk of cucumber
A few leaves of either - endive, arugula, swiss chard, garden cress, chicory greens.
These veggies are things that I know my guinea pigs will happily eat, and that I can find readily available from my local grocer or supermarket. I steer clear of things like parsley, beet greens and spinach which contain high levels of calcium. I also avoid things like broccoli, cabbage and brussel sprouts which can cause gas when fed frequently.
They get fruit no more than once a week, and even then it's only something like a small slice of apple or one strawberry each.
Remember to introduce each new vegetable gradually and in small amounts! Sudden changes in their diet can cause bloat and diarrhoea.
I hope this helps, and congratulations on becoming a new piggie owner
