Picked up a Mossberg 500 in .410 and I love it so far. 

I have to wait until we get a warmer day with no wind before I can go blast away with it because I'm not 100% over the pneumonia I had.. 

Can't wait until chicken season....woohoo..

So who all uses a .410 for birds?

Count me in ,just a lowly single shot though.
That pump sounds sweet.
Ever look into .410 customization? It is remarkable the performance you can get out of them.
Not that you can use it here for big game unfortunatly but guys report getting 45/70 performance out of them with custom slug gun set ups.

Sweet little gun Sonny you'll love it. Bought one for each of the boys over the years and they have had nothing but good service out of them,, oodles of grouse taken with them.

Personely I shoot a plane Jane H&R single shot,, been packing that one for 25 years now. Nothing fancy and that's what it s about nothing to fail. Your grouse count will go up significantly with a .410 in hand. I personly shoot 3" with #4 shot. It sounds a little over board but you can get out there and reach them with this load. As well with the #4 there are less pellets to mess up the bird. Just a nice clean head decap with maybe the odd pellet into the breast that is easily cut out with no damage.

Yup you'll enjoy it.