Can you put peanut hulls and chicken bones down garbage disposal on septic system?

Yes, you can put them down the garbage disposal, but it will fill your septic tank with debris that will not easily break down. This means that it will fill the septic tank with material that will cause you to have to have it pumped out sooner then if you didn't put it down the drain. Depending on the quantity you are talking about, it may or may not be a big deal. Certainly an added cost that is easily avoided by disposing of these items in the solid waste trash stream.