I've read very often not to mix grit or oyster shell with your birds' food and the reason is that it doesn't allow for self-regulation and so they will be "forced" to ingest more than they need. I don't understand this. My birds seemingly have laser guided accuracy when it comes to food. They can nail a mosquito out of the air while on the run. Their vision is superb at the distance between their beak and the ground. When I hold out a handful of scratch I know in exactly what order they will eat the grains. If there is a sunflower seed amongst a bunch of oats they will nail that seed dead on every time. They can tell the difference between a grain of barley, a kernel of corn, and a pellet of feed. The point is, I just cannot see them accidentally ingesting grit or oyster shell. If they ate it, I'm darn sure that they meant to eat it. Maybe it's more of an issue if you feed fermented or wet feed where everything sticks together, but I just don't see it being a problem mixing it with pellets. If someone has a more compelling argument for not mixing them, I'd love to hear it.