While I debated having my first post on a Catholic forum be about cat litter, I did want to say I've used chicken feed for years both to avoid my cats inhaling clay, silica, perfumes, etc and to save money. It works very well for us and our 5 cats. As far as dust that contains gmos, it's certainly possible, but I still feel better about that than the clay or clumping type dust. Clay dust causes breathing problems in my husband so it's just not an option. In addition, the chick starter doesn't contain antibiotics, so no worries there. The medication is a thiamin uptake inhibitor to prevent coccidocis from developing. No harm to mammals at all. I just use the layer crumbles feed anyway. I am an experienced chicken owner as well.