If dead chickens with H5N1 have washed up on the North Lantau coast, I agree with Captain that this is the most likely source. Although the time lag since the bird Captain mentions seems a long time, there have previously been similar dead birds (dead geese?) washed up on north Lantau. Dead birds like this would be an irresistable food source for crows.
Previous reports from Hong Kong have shown that scavengers such as corvids are particularly prone to H5N1 here - it is likely that these birds regularly pick up H5N1 from dead birds. Most wild species show no evidence of carrying the disease.
