So the photo comes from the flockbook on a Dutch site, Blauwe Texelaar. And it's really very interesting. For example: "The use of the term 'blue' (in Dutch: 'blauw') originates from the fact that although the fleece looks white/gray or brown the colour inside the fleece is steel blue." emphasis mine
Apparently they are calm and nice to get on with, and I will say that the lambs are very cute.
The Blue Texel is a color variant of the normal white Texel sheep. The Blue Texel came from white Texels who carry the color factor "blue" with them. This factor is a recessive factor. From a mating of two white Texels who both carry the factor for the blue colour, there is a 25 percent chance blue lambs will be born while a mating between a Blue Texel and another Blue Texel always gives blue lambs. Texel sheep evolved as a result of crossbreeding the Dutch polder sheep with several English breeds, such as Leicester, Wensleydale, and Lincoln at the beginning of the 20th century. Today, as a result of efficient selection, the Texel breed has developed into a meat-type sheep of outstanding lean meat quality that has become popular throughout the world as a sire of crossbred slaughter lambs. When Texel lambs with a different color were orginally born, most breeders were very ashamed of this. It was not until the late 70's that some breeders started with the breeding of this rare colored sheep: the Blue Texel.