Hey Larry!

Silos are a very dangerous place! Mainly because they collect gases such as methane, and others. You don't want to mess with pigeons in a silo!
Go to the barns! That is where you will find the majority of pigeons. Get permission 1st from a farmer you have noticed has alot of them flying or sitting around the farm yard in daylight. Go there at dusk and climb up into the "haymow" with your flashlight, larger fish landing net, burlap sack to keep them in. They will be "roosted" @ dark & most will just sit there and be caught very easily. It's really quite fun once you find a safe barn and a friendly farmer with alot of birds around. The main "post-catch" idea is to have a larger outdoor pigeon coop, outdoor cage to keep them in once you bring them home. Cracked corn works well for feeding them and a larger dog dish for water works. Best of Luck!

The Lab-Man (Labrador owner/trainer since 1963)