Duck help

[Dbinn]

My husband and I just spent A LOT of time adding this duck area to our barnyard. I did lots of research and everyone said “pea gravel”. Well now all 4 of my ducks are getting sores on their feet from walking around in the pea gravel . Please give me cheap ideas of what to cover it with to protect their feet.

 

[Crazy Maizie]

Pea gravel should be smooth enough. But, I use a coarse sand in my run. I've been doing so for a few years with no issues. Not sure what to advise you to change the substrate to.
Do the ducks have shade? The gravel might get too hot if there is no shade.