I visited the Colombo Zoo in December 2016, and this sign is still there and the neighbouring section of land still looks "like an abandoned construction site". In ten years (going by the 2006 date given above) nothing has been done with this - not even taking the sign down!
However, looking at the other photos posted in the gallery from this time, the zoo no longer has an apparent issue with starving and crippled animals. While the zoo is still not a good zoo, the animals are at least being fed properly.
