It should look like a firm brown tootsie roll. Not like rabbit poop, and not white.
Chalky indicates too much bone. That can be a problem with the pre-mixes. They just contain too much bone. You can keep feeding it. Just do a meat only meal every other time or so. Or cut the amount in half of the premade and add in a couple chunks of meat. That will significantly reduce the bone content.
"Having heard all of this, you may choose to look the other way.....
but you can never say again that you did not know." William Wilberforce 1759-1833