Yep. It is a Swarm Pokemon.
It can be caught on Route 1 with a Swarm. Level 2.
A Poochyena can be obtainable
-By Trading a Mightyena and Breeding via the GTS or a Local Trade.
-Trading one through the GTS or locally
-Transfering one from Emerald to DPP via Pal Park and trading it to HH/SS