If I have 10,000 PDFs, some of which have been OCRed, some of which have 1 page that has been OCRed but the rest of the pages have not, how can I go through all the PDFs and
If by OCRed you mean that they contain the text in machine-readable form, you could use a library like Apache PDFBox to try to extract the text from the second page of the document. If it throws an error or returns garbage, it's most likely not OCRed.