Why do some Winter Whites still change colour and others not?

[slatted]

I got two sapphire males from a breeder and they have been housed in cages right next to each other but whilst one is still the standard colour his brother has been changing for weeks and seems to be getting whiter still.

Because they are siblings I would have thought they both would have changed.

Any ideas?

[BluerayDarkes]

None at all. I got a winter hybrid called Lunar, last year when we got him he was white with a grey stripe, then he changed to his summer agouti coat. So far he hasn't changed back to his winter coat, and I can't figure out why that is.

[slatted]

I must say that Pumpkin, my normal WW changed a bit last year but this year no change at all.

Rainbow (ironic, I know) is like a negative of his summer self, white (ticked a bit with brown I think) with a bit of darker brown where once was beautiful sapphire. Still beautiful now but a bit different and much harder to spot in the sawdust! lol

[BluerayDarkes]

Interesting that they change or not, I find it rather exciting to watch see if they change coats.