Same brew, Same temp, Same yeast,=one ferments, the other not! WHY!?

Doesn't make sense!
Somebody help me figure this one out!
Facts of the mystery: 10 gallon all grain brew of winter Lager. No problems to report during process. I use 15.5 a sanke keg as my BK and drain the wort out through a ball valve into 2 seperate 7 gallon plastic ferment buckets. I fill up one with 5 gallon then the other. Both fully sanitized. OG=1.061. Both packs of Wyeast Bavarian Lager were started 2 hours ago. added oxygen through stirring and stone with tank. Put in fridge with temp controls set at 55 F.
Mystery: It's been a week, one has been bubbling with a healthy dose of Krausen while the other nothing, not a peep. I stirred 3 days in=nothing. I re pitched a new wyeast 3 days ago and still nothing!
How can under the same variables one ferments and is almost done while the other refuses to do anything! No krausen and still original gravity. What I'm I forgetting as a factor?

Yabo72 said:

Both packs of Wyeast Bavarian Lager were started 2 hours ago

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What does this mean? Were these smack-packs? Were they both fully swollen? Been a while since I used Wyeast, but I thought they usually took longer than 2 hours to really get going.

IMO, this is the most likely source of the difference.

Yes, these are the smack packs and the instructions on the back say to smack it 1-3 hours before pitching.

Yabo72 said:

Yes, these are the smack packs and the instructions on the back say to smack it 1-3 hours before pitching.

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Did they both swell? I would go by that rather than absolute time.

Edit: Oops. I can't read. Please disregard.

How can under the same variables one ferments and is almost done while the other refuses to do anything!

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They're not exactly the same; two different smack packs, plus you sanitized the two separately, maybe you didn't rinse one as well, if you used bleach, for example. Also, as you said, you filled one then the other. Perhaps the chilling was different and shocked the yeast. Really though, this probably wouldn't change the fermentation to a "yes or no" state, just have the two taste a little different.
All that said, corax is most likely right; the second smack pack likely had something wrong with it. One big starter split in two is a good way to go for "identical" brews.

Do you know what their manufacturing dates were? If the bad one was even a couple months old you'll have pretty bad viability.