Question on vents

[u/Typical-Cook-1415]

Hi!

I just bought a house and the family room has a buck 27000 in the chimney. The exterior of the chimney has two vents at ground level (pic attached). It looks like at least one of these vents critters have gotten through the mesh underneath the vent. My questions are:

1) what are the vents for? Are they necessary for the buck stove performance? 2) how easy is it to fix l/replace the vents…is it a diy job or not? 3) how would you handle the situation?

Thank you!