FSMA PC for food for animals. 3rd party audits?

Under FSMA preventative controls for food for animals we are required to register with the FDA. Do we also need to have 3rd party audits and who would we go to for that audit? (Pacific northwest of the US)

Further information: we are already registered with the FDA for human food and do 3rd party audits through Primus at a separate plant for a different product. This is not a human food by product. I expect that I can update our current FDA registration to include the animal food, but Primus has already told me that they will not include animal food in their scope.

I've got an answer from the AFIA.

the answer is no, 3rd party audits are not required (for 21cfs507) UNLESS you are going to have a supply chain preventative control which the FDA has said will only apply to a very small percentage of companies. The FDA will still do auditing after you've registered with them, but it is not required to also comply with Primus, fsms, or another auditing body.

For me this means that the FDA's "Guidance for industry #235" contains all of the requirements that I need to meet and there won't be additional requirements. That was a question because in our human food facility the FDA may not require a certain thing, but the Primus audit would require that thing (quick example is flow charts are not required by the FDA, but are required by Primus).