[Jacob-list] Stress, Mineral Deficiency, or what?

[MarmontJacobs at aol.com]

Hi all,
       Great to read about everyone's lambs...Today I was shearing a couple 
of shearling ewes - just in case we in the UK get to show this year...when I 
again came across something that puzzled me last year. Last year, I 
outwintered the shearling ewes with hay and a mineral lick, plus a feed block 
in the colder weather which wasn't much. When I came to shear them in May, 
they all had a "break" line in their fleece especially noticeable around the 
neck where the wool was thinner and markedly grey in the dark fleece over 
about half an inch - corresponding I suppose to around February time when we 
had a cold snap. 
    Today I found the same on one of the two shearlings - this time all 
inwintered with minerals, block, and hay (not home grown this year due to 
foot and mouth and therefore not having any possible homegrown deficiencies)! 
The two young ewes I kept back from the previous year have recovered their 
dark wool. Any ideas as to the cause? I have heard of breaks in fleece, but 
never loss of colour.
    Trisha M-S
    Marmont Jacobs, Norfolk, England