Please tell me this is normal dog behavior....

Banjo was playing outside and came in smelling really bad. I've noticed this smell on him before. We were on our way out to see a movie so I wiped him down with baby wipes and figured I'd give him a bath when we got back.

I let him outside to go to the bathroom when we returned and to play a little before his bath. There's a section in the backyard that he keeps rolling in. I've never paid much attention to it. It's way in the back (we have a big wooded lot and only maintain the first half closest to the house). Putting two and two together I thought it's about time I see what has him so fascinated with that section of the yard so I hiked back there.

The area is covered in ivy but he's rolled around and flattened it in one section. He's been rolling around on top of a very dead bird. The bird smelled awful, just like him. He's been rolling around getting the scent of it all over himself. It doesn't look like he's eaten any portion of the bird, just rolled around on top of it. I have never heard of this type of behavior in a dog.

I gave him two baths but I swear I wanted to wash him in bleach. Any clues on ways to curb this behavior short of fully scoping the yard before he goes out? I have a ton of hawks and owls in my area so it's really hard to control the occasional dropped dead snake or baby bird (he's been caught rolling around with a dead snake before). The only thing I can think of is the expense of building a second fence to keep him out of the more natural wooded area.