Thanks for the informative replies!

I didn't think about it but, over the summer, my youngest sister and I had been taking him on walks in the afternoon. I don't recall much of a change in his barking, but, I wasn't trying to keep any records either.
I do remember that while on the walks, he seemed to listen to my sister better when it came to sit and heel commands then he did with me. He would always pull on the leash when I held it, and with her he would stay only a step or two ahead.

I am not sure how the Kong would work out. He doesn't seem to know how to play with toys. We have tried to give him an tennis ball with a treat inside, and he simply ignores it. He won't chase anything, even if we show him there's a treat inside. Same goes for big bones and other toys.

He does however randomly play with things on his own. I got him on camera one time, dragging a 5 foot branch that had fallen in the yard. He would run a few paces, drop it, run around it and bark, then nip at it a few times before he finally picked it up again. Then he would repeat the process.

I will have to walking with him again and this time stay on it. Will try to keep you posted as well.