As Ly said, you should take a look at the veggie chart HERE
The rule of thumb is to feed at least a cup of mixed vegetables daily. It seems to me that you're not feeding a big variety. Variety is the key to a healthy diet.
I start with two lettuce-type veggies. Here's an example: today I used green leaf lettuce and cilantro as the base of the diet. Then I cut up a cherry tomato, a 1/4 of a yellow bell pepper, and added two baby carrots. I also added a few sprigs of parsley.
The key is to feed at least two lettuce-like greens and a 1/8 of a bell pepper daily (to ensure Vit. C intake), as well as other veggies.
You cannot feed everything everyday. You've got to switch it up daily. Also, do not feed veggies that have high amounts of Oxalic Acid or Calcium daily, as these can lead to sludge or bladder stones. (Bad for piggies)
are some sample menus that can give you an idea of what you can feed your pigs.