Feeding a colony of 12 ferals

Im looking to find a cheap but healthy food for ferals. Im a senior citizen and on fixed income. I would like to feed a high protein, quality food that is cheap. Ive tried getting help from a few rescue groups but it seems as though you need to be in the loop to get help and if youre not, forget it. Ive been feeding TSC'S paws and claws brand but they're not doing as good as they were on it. I think they may ha2vr changed the formula. Any thoughts?

Check out Tractor Supply Company for their all stages food. I have heard people say it is pretty good, a 18 pound bag is $20.  

http://www.tractorsupply.com/tsc/product/4health-all-life-stages-cat-formula-18-lb-bag

My cats eat a higher protein food so I can't speak from experience but for the price point it has a good protein percentage and fairly decent ingredients. 

Yes, 4Health is good in the mid-price range. If that's too much, for cheaper foods I find that they do best on Purina Cat Chow or Friskies. I think Purina must have a better vitamin mix.

If you have a Costco membership their dry food is good, costs about the same per pound as Cat Chow.

I have 3 feral kittens that I found in my shed in another city and the mother and littermate are still there.  I feed them a mixture of Purina Cat Chow Complete and Friskies.  Purina a 22 lb bag at Walmart is 17.78