Happy Birthday!
Are you a freecycle member where you are? Also, check with print shops (The Printery here in Pt Townsend ALWAYS has pallets made of nice hardwoods, and about a third have decent plywood on one side. 1/8" hardware cloth on Amazon is the cheapest I've seen anywhere out where we are.
good Luck!
1/8" hardware cloth is cheap because it's very light weight and isn't strong enough to keep out predators.
for more on her look at the thread : crazy hen dont know what she is