To whomever mentioned that her ferret was turning orange/brown:
 
I don't know if this applies to you, but I have a friend (fellow vet
student) who has an albino male who started to turn orange.  Turned out it
was the carrots she had been feeding him -- the pigment in the carrots made
his skin turn orange.
 
To whomever asked about the clinical signs of heinz body/hemolytic anemia:
(Sorry I have a horrible memory for names and I tend to delete too
quickly...) I don't have a clear answer...the clinical signs of anemia depend
on the severity, the chronicity, the quirks of the individual animal, etc.
 
In a sudden onset of anemia, as with onion toxicity, you may see weakness,
lethargy, pale mucous membranes (especially the gums or eyes if albino),
exercise intolerance...signs of oxygen deficiency or blood flow problems.  A
slow developing anemia may not show any signs except for pale mucous
membranes -- animals can adapt amazingly well to adverse conditions at
times.
 
In general, onion toxicity causes oxidative damage to the red blood cell
membrane, in particular to the proteins in the membrane, causing Heinz body
formation (Heinz body = denatured protein, I think :)).  In dogs, Heinz body
anemia is usually associated with hemolysis (clinical signs occur several
days after feeding onions).  Hemolysis is the break down of red blood cells,
of which there are two types: intravascular = within the blood vessels, and
extravascular = within hematopoeitic organs like the spleen.  In dogs the
hemolysis is mostly extravascular, but there is also an intravascular
component.  Extravascular hemolysis can result in an enlarged spleen.
Hemolysis can also lead to a condition known as icterus = a yellow
discoloration of the skin/mucous membranes/sclera due to excess amounts of
bilirubin, a break down product of hemoglobin in red blood cells.  Icterus
would be easily seen in an albino ferret, but may be difficult to see in a
pigmented ferret.  Excess bilirubin can be detected via blood test (chem
panel).  In cats, Heinz body anemia can occur with or without hemolysis, and
cats tend to develop Heinz bodies quite easily (due to the structure of
their red blood cell membranes).  I only mention these other species because
I don't know exactly how ferret red blood cells react to oxidative stresses.
 
By the way, acetominophen (Tylenol) also acts in a similar way of oxidizing
red blood cell membrane proteins to cause a Heinz body anemia.
[Posted in FML issue 1605]