rocks on rain barrels

Do not cover the rain barrels holes with the rocks! this then covers the holes which prevents rain water from going in. We place the rocks next to the holes which prevents strong winds from blowing off the tops.  Someone may place a metal netting over the holes to prevent squirrels or what not falling in and drowning. I can help with this next week sometime for I think we have a form of metal netting that may work in the shed.