I would highly recommend the following resources for some guidance on managing an aging workforce and some productivity issues:

1. https://alis.alberta.ca/media/2894/agingworkforce.pdf
2. https://www.brookings.edu/blog/up-front/2013/06/10/is-an-aging-workforce-less-productive/
3. https://www.bankofcanada.ca/wp-content/uploads/2010/09/beach.pdf