To get a full town of deer is pretty hard. People want tons of bells for Diana, Beau and Fauna. I am lucky most of my villagers are my friends' villagers or my starter/campers.
Another thing is keeping your villagers is hard since there are only 10 deer villagers. If one of them leaves there's no way of substituting him/her back (unless you go through 16 villagers cycle). I have to make sure all my deer villagers ping me everyday and check to see if their pinging for moving away.
Also when I got closer to completing my deer town. I found cycling through to get the non-deer villagers out is hard cuz I had to make sure all my villagers ping me.