that's one of the drawbacks to free ranging...they can go where ever they want!
Have you checked high up for him? any tall trees nearby? what about his lady, is she still hanging around? how long has he been missing? Any other peafowl near you? could he have wandered over looking for another mate? At 2 years old they will be mating this year, maybe he's looking to get himself a harem of ladies and not just the one.
Well, not to let you down but my first pair of peafowl I got I free-ranged. Both birds were at least 3 years old and they did pretty well for a month or two...Then the peacock was gone. We know for certain he wasn't stolen or killed because a month later someone across the street was heard talking about seeing a peacock in their yard a month ago. Well then all these people were seeing and some hearing a peacock in the neighborhood but we couldn't find our peacock! The peahen eventually tried to find him too. She left and luckily we caught her in a person's backyard. Then one lady said she hand feed a peacock that came to visit but it didn't stay long. My peacock has been gone since Christmas of 09, so I am pretty sure he is NOT coming back. As for the peahen she now lives in a pen with four other peafowl and a different peacock that she loves even more.
I would search for him. It is weird to find the peacock missing but the peahen still around...I have no idea how mine got separated like that. I think my peacock didn't like the peahen. He probably went looking for better peahens. If you do find your peacock maybe you should try and get some more peahens...Or pen them up and just free-range their offspring. Put out fliers saying missing peacock and talk to neighbors. Our peacock never stayed at each house long. Each person we talked to said he stayed less than a week maybe like two days then left. He seemed to be really traveling too so he probably was searching for other peafowl. Mainly talking to a lot of people and giving them your number so if your peacock does show up they can call you is a good idea. I hope you can get him back.