[EBB Sightings] Oregon Junco w/o tail feathers

Here in Hercules (Refugio Valley area) our back yard
is frequently visited by a female "Oregon" Junco
without her tail feathers! She is shaped kinda like a
baby chicken-- disguised as an O-Junco! I keep waiting
for her feathers to grow--but NO--she has been
visiting us for several weeks now and no new growth
seems to be occurring in her rump area--and she
doesn't seemed hampered by the lack at all! This is
new to my eyes and I wonder--So whats up with that?!
Any thoughts or info appreciated.
Sweet Tweets,
MaryLou Mull
Hercules