Hi Gijs,
Yes, Canonical pulled the Saucy packages from the standard archives. It was EOL'd a few months ago. They're still available via an alternative server but until you change any machine's apt sources list they will fail.
The farm will automatically retry any package with all upstream jobs passing each night. There's no need to rerun bloom. I see the job you linked to is in the queue to be rebuilt already.
Note there's a lot of backup at the moment due to a recent core release. We're rebuilding several thousand packages at the moment. The queue is down to ~3k from 6.5k jobs last night. We're running 20 build machines but I expect it to need another 24 hours or so.
Tully