I have stupidly laid back pigs (ask All About the Animals Claire!) and Jeff and Boxy don't bat an eyelid if you approach them (as long as you don't make them jump, and you aren't appearing with the promise of food!)
The main thing is, that as a Milo Mummy, you know his behaviours, quirks etc. so you're the best person to answer your own question. Has his behaviour changed? I'm thinking along the lines that it may be indicative of something, or you wouldn't have been concerned enough to make the post, but like I said, you're the best person to judge whether there's potentially something wrong.