Been there a while?

This guy called and said someone had abandoned a beehive in the back yard of a house he was trying to sell, could I remove it.  I took a look at the situation, and found that someone had put a nuc {the white box in the bottom of the picture} next to an entrance bees were using to get into the wall.  I used my infrared camera and saw that the bees covered from floor to ceiling.  We came back and took care of the job. We had guessed that the hive had been there a long while because it was so big, when we opened it up we saw nothing but black comb.  That means the bees have been there years. We cut and scraped comb and put the brood into a nuc.  For as large as the hive was I was surprised there weren’t more bees.