Agreed! 19 gauge minimum half inch by half inch hardware cloth and make your strips of hardware cloth long enough that you can extend it out at least 1 foot on either side of the run as an apron/skirting.If you have raccoons then I highly suggest replacing the chicken wire with hardware cloth. Those suckers can tear that chicken wire open like it's nothing.
Edited to add I didn’t see the cement blocks you have as a foundation so skirting may not be needed but you have to ensure they cannot dig under or pull under the bottom of the hardware cloth.