As I stated and other have commented, chicken feed is for chickens and can contain too many vitamins for chamelons, as can alfalfa pellets marketed for rodents as a complete diet. Aside from chicken feed being full of too many vitamins, it is composed of indigestible fillers and grains that offer very little nutrition and grains are known for causing inflammatory responses in animals that don’t normally consume them. In short, chicken feed is fillers and garbage, left over from the human food industry and “enriched” with vitamins and mineral to account for what those non-nutritive grains lack. Take a look at the ingredients on an bag of chicken feed, you’ll see things like wheat middlings, soy, and similar junk, which binds calcium and provides nothing.
Will it kill your chameleons, possibly and likely not, but it also isn’t doing them any favors.