Wouldn't all the wild birds that eat insects be sick and dying if it was so bad for them to eat bugs and worms????? I think a healthy chicken will be just fine eating natural food like that.
In my personal opinion that is a lot healthier than taking a soy based food (which has to be cooked and processed to remove the toxicity of raw soy) and filling it with artificially created "vitamins" and calling it the healthiest possible thing to feed our animals.
Just my opinion.
We have fed ours a homemade mixture of whole grains and seeds along with a little seaweed; scrambled eggs, and yogurt. We give them worms and pill bugs when we find them and have put them in a bottomless cage outside every day since it has been warm enough. We have 8 wk old chicks, 3 wk old ducklings, and 2 wk old chicks. All are happy and healthy so far. We had one mildly sick chick in our first batch, but feeding vitamin/sugar water in a dropper several times a day seemed to do the trick. We have had no other problems so far. The only chicken we have lost so far was to a fox attack last week.