Dien,

Excellent example of those wonderful Unusual and/or Unique, Niches, Business models etc...

Another interesting detail about the Avian business you mentioned. Lots of other Keyword related Domain name phrases bought up and Pointing nicely to their main Web concept, not all visible here, but...
https://www.google.com/search?q=link...ashions.com%2F

Other Smart stuff happening throughout their Site with More Good Lessons, well worth Digging into and Reading...
http://www.flightquarters.com/bird-diapers/SMAP.html

Also, I believe, Very deep into the SowPub archives, Avian related discussion(s) and opportunities do exist from the past... Chicken type opportunities, still Booming and Growing, Nicely {Evergreen} included Too!

So... Are there Other ways of Getting into these businesses Using Different ideas and methods...

Definitely possible with an Open mind and a little More Thinking! ...

Quick example! Huge resource, Traffic galore & other Great connections/communications ...
https://www.google.com/search?q=avia...en-US:official

All the best,
Phil