All above suggestions are great, but I am interested in your statement that you moved two of the plants "maybe some needed more sun so I dug up two and put in pots for even more sun" Certainly if you had them shaded by other tall plants, like those killer gorgeous tomato plants in your last picture, they could be yellow, stunted and growing slowly. They do need full sun! Have the two plants you moved shown signs of recovery?
Also, if composted cow manure is the only fertilizer you have given them it could easily have been used up by now. It's fairly low-dose and releases nutrients fairly fast. I'd look for a better fertilizer, as well as checking on drainage and soil aeration etc. Epsom salts is a great help with greening up plants, but very soluble, so possibly dissolving it in a watering can and just 'dosing' all your plants with the solution on days when you don't run the irrigation (so it doesn't get washed through so fast) might make it more available to the plants. I give mine a dose about every week or two.
Back to the great looking tomatoes and squash plants in the last picture, they make me wonder how it could possibly be a soil or overwatering issue, since they are doing so well.
One more observation from your pictures, the two plants in the first picture look like they are different varieties, and so they might have different color leaves even if they are healthy.
