Did you carefully sort and see each fish that was stocked? I know I have been guilty of just inspecting the stocker fish 'en masse' in the buckets, maybe randomly lifting some of them, but not actually going through them fish by fish. Granted, that can stress them but it would be the only way to be sure of what you're getting.
And even doing that, some of the smaller BG can be difficult to distinguish from other similar species. At least for me.
I've seen the 'bird stocking' scenarios discussed on the forum before, but can't recall if any sort of consensus was reached. IIRC the thinking was 'not impossible but almost so' unless the two BOW were close together.
