Cool, a new goat forum!
The term is FOUNDER, not flounder (isn't that a fish?!). I know for a fact horses founder, think cattle can too. It is caused by a rich diet, or one that is made rich too quickly, i.e. no grain to two pounds a day.
For grain and alfalfa pellets, we use 4" pvc pipe with caps on each end, then take a jigsaw and cut it in half lengthwise. We make ours in 4' sections. Next take a 2"x6" board and make two pieces about 12" long. Cut a "V" into one end of each. Then screw these 2x6 boards onto two 2"x4" board, roughly cut 20" long each. So imagine you'll have an upside down "T" with the 2x4 on the bottom and the "V" end of the 2x6 pointing up. Then you'll want to take your PVC section and set it onto the wood pieces with the wood towards each end and screw the PVC down to the wood. You then have little troughs for the goats to eat grain out of. They last pretty long. Mine are 4 years old and starting to need replacing of the wood.
ADM has wonderful pelleted goat feed. Quality ingredients with no animal products or urea. They have a dairy line and a meat goat line.
You should watch the molasses intake on your goats, something which Purina Goat Chow is loaded with. Causes acidosis of the gut, which can lead to bloat and death.
Chicken feed is terrible for goats - it has MEAT products in it and some is medicated. Why even go there?