For my Bruno – a 14.5lb Rat Terrier-Jack Russell mix, we gave him antlers since we adopted him at 4-5 months of age. We also gave stuffed Kongs, bully sticks, fish skins, Nylabones, Himalayan dog chews, etc. He is a moderate chewer nowadays so he still gets the same things, plus stuffed and frozen hooves.
For a heavy chewer, stuffed and frozen Kongs would be your best bet, I believe. I never had a problem with hooves or antlers, even when Bruno used to be a heavy chewer in his puppyhood, but just make sure you always monitor your dog when chewing on toys to prevent any disasters. Bruno used to try to swallow 2-3 inches of fish skins whole, so we started putting vice grips on them, and now he chews them up all the way properly.
