Minecraft – Can Pigs with saddles mate in Minecraft

Reportedly at PAX (summary) it was said that they have a two-block reach: you'll want to have a one-block buffer zone between the fence and anything of value.

The reach, based on the pictures I've seen of the Endermen's destruction (and my own experience), appears to be directly in front, 1-2 blocks laterally, and from ground to eye level. Diagram:

Enderman facing to the right -> o ..
                                o ..
                                o ..

o : Enderman body
. : Blocks that are fair game

Evidence of Enderman mischief:

• Two blocks above the ground
• One block above the ground
• Ground level

Coincidentally, this mirrors the one-block buffer zone you need to have for beds in order to sleep undisturbed.

Interestingly, vines might be a better alternative to fences, if you're okay with the appearance: Endermen will take the vine block before taking anything behind it. Since vines automatically regenerate, you'll have a defense that's more compact than a fence with a buffer zone.

The conditions shown in your screenshot should be able to spawn pigs, assuming it's a pig spawner. I did a rough recreation of your setup in my world.

Even in the dark, pigs were spawning, and within seconds of placing the spawner, so it's not as if you aren't waiting long enough. (Yes, the pigs also spawned when I surrounded the spawner with Glowstone). Because of this, I have a feeling that the spawner in your image isn't actually a pig spawner; it's likely a zombie spawner, or some other hostile mob. This is especially likely if you found the spawner and it wasn't manually placed by anyone, since there wouldn't be any natural pig spawners around.

Like Kevin Reid said, you could test this by making the room dark and seeing if any hostile mobs spawn. If you have admin privileges (and don't feel like this is cheating in some sort of way), you could use /give 52 1 to give yourself an actual pig spawner, place it in the room, and see if that one spawns pigs, just to verify if this is an odd SMP glitch that is only happening for you.