Yes, the openings are too big. Personally I don't use anything big enough to let the animal inside put its head through (otherwise something on the outside can grab its head). Even for adult standard ducks I never use anything with holes bigger than 25mm x 25mm (1 inch by 1 inch). And I don't have a raccoon problem either - it's also important to consider whether a predator could reach through the mesh too.
I heard that you cant use chicken wire with chickens because they can bite through it? is this the same way with ducks? or another reason it cant be used? i found it with the one inch hexagon openings.
Chickens and ducks can't bite through chicken wire but dogs, coyotes, raccoons etc would have no trouble tearing through it. I use welded mesh panels with square holes. The wire in these is 2.5mm thick - about 1/10th of an inch. Mesh that is about half that thickness (i.e. about 1.25mm thick) is ok too though but I wouldn't use anything thinner than that and definitely not the hexagonal chicken wire.