kattabelly
Crowing
That isn't enough to keep very small birds out, but those birds are lower risk anyway. Gulls and wild waterfowl are the main species you want to keep away from your birds.The gaps are 2.5 cm by 7.5 cm
Are these gaps small enough not to be a problem?
Personally I won't bother trying to keep the local wrens out of the run even if housing requirements are brought in here. If you did want to be more thorough about keeping any wild birds out though, just really thin plastic net (like the stuff sold as butterfly net or to keep leaves out of ponds) is enough if you're attaching it to sturdier metal mesh.
