I have to agree with Deena's Mom - it sounds like he's bored with an abundance of energy. Your challenge is to drain his energy and get his mind working.
Some of the things we do/have done:
- My "kids" go to daycare for 6 hours Mondays and Wednesdays - so their energy has been drained.
- On non day care days, we walk every morning before I go to work. But they are not sniffing meandering walks (those are for the afternoon). We do a pack walk where they are focused on moving forward as a group. We also stop and do some obedience practice throughout the walk. For Zeek who's about 20 mos old and has a fair amount of puppy energy, I have been known to put a backpack on him with weights in to (no more than 10 to 12%) of his body weight. (You can make one side of the backpack slightly heavier than the other to keep them working on keeping it all balanced.)
-When we get home from our walk, I feed them. Zeek I feed out of a puzzle feeder.
We do walk then eat as it taps into their natural biological rhythms of hunt, eat, sleep. (I don't know if it's true or not but I can tell you that mine crash out and sleep for at least four hours.)
- When I can, I come home at lunch and either take them for a short walk or play in the backyard. Then we feed lunch and then again, they are crashed until I get home.
If you can't come home at lunch, can you get someone to take them out for play or a walk or even just drop off a Kong with lunch frozen inside. If you can't get/or don't want someone in your house, you can get automatic Kong dispensers that will drop Kongs at specified intervals.
Just some thoughts.