But he does have lice so we are already treating him for that.
A daily bath with Borox should do the trick on the lice, and maybe a dusting in diatomaceous earth when the bird is dry. You may also look up some commercial products sold for delousing pigeons, as there are several.
I would like to build an outdoor aviary for him on the front of our garage and cut a passage to an indoor enclosure so he can come in and out during the day.
This is a way to go. I know two different folks around me who keep their pigeons this way. So long as you don't mind using the indoor space for birds, and modifying your garage, it keeps things simple by not having to build a loft and you also don't have to worry about weather problems as much (although pigeons are quite hardy). Ventilation with this option will be something you should pay attention to. I have found the best materials for building aviaries is 1x1" lumber (pressure treated if it will be outdoors) and 1/2"x1/2" mesh wire fencing or cage material (sold in the garden fence section of Home Depot), which can be easily cut to desired lengths using wire sheers, and use regular nippers to clip off the sharp ends if they stick out.
I think we can give Pete what he needs to be happy.
It sounds like it, but if you intend to keep Pete, I think he'd be most happy with a pal or two. Pigeons like the company of other pigeons. It doesn't take much more effort to keep several pigeons, only the added cost of feed, which IMO is negligible. Below is a link to a list of breeders, which you can filter by state. Not sure how old it is, but worth a try to buy a few young birds to put in with Pete. Pigeons are gregarious critters and love company--there may be some pecking and wings flinging at first, but it will only last a few days and in no time they'll be preening each other and hanging out like buddies.
http://mumtazticloft.com/PigeonBreeders.asp
We do live right in the middle of ST.Louis MO so I'm having a hard time finding grit..I might have to venture out a little further to a feed store to find it..also my local petstore quit carrying Diatomaceous Earth!! Why?
Try Foy's Pigeon Supplies (link below). They have all the good grit you'd need. I recommend just the standard red grit. Buy a smaller bag like 10lbs otherwise shipping from them will not be economical.
http://www.foyspigeonsupplies.com/OrderRetrievev2.aspx?CatalogueID=0
I have found diatomaceous earth online on
Amazon. In addition to dusting a bird with lice, it is also good to clean the loft area with from time to time. I use a duster thing, which just sprays the dust for you rather than having to scoop and sift it yourself, they are only like $5.