Pam, my Pica just turned 2 years old and has been a biter since she was
just a tiny kit.  Everyone said she'd outgrow it, but no, she goes for
the ankles and feet and has drawn blood regularly.  I've tried the Bitter
Apple, the time-outs, the nose-thumps (before I learned otherwise), and
nothing ever worked.
 
I discovered a new little trick a couple months ago.  I keep a spray bottle
of water on my desk, so when she decides to take a bite of foot, I give her
a little squirt on the top of her head.  She totally hates that.  I might
have to squirt her several times (along with a verbal warning) but she's
taking the hint; at long last she's learning.  I still get the occasional
nip, but she hasn't made me bleed (not even while I'm wearing socks) since
I started using the water bottle.  It's harmless and she hates it.  Good
luck and I hope this (or something else) works with your boy.
 
Wendy and House Penferret: Boobah, Buttercup, Pica, and Flower
[Posted in FML issue 2962]