[Tulip23]

Keen to avoid vet visit if possible:  Anyone any ideas/experience of hair loss on lamb's ears?   My micro flock of 8 lambs (Suffolk mule x Grey Faced Dartmoor) aged 4 and 5 weeks old still with their mothers have gradually been losing more hair/fleece/coat from their ears.  The backs of the ears - exposing pink hairless areas that I anticipate them becoming sunburned in the near future.   Totally asymptomatic with no head shaking or itching noted. 
Mothers seemingly unaffected.  One or two are worse than the others and one or two have barely any loss. 
I have a cade lamb at home and no signs of loss.

Called vet this evening and she wants to come out and take skin scraping and bloods.  Sounds expensive and wondered if anyone else could shed any light please? 

[SallyintNorth]

Might be a reaction to a plant (bog ashphodel came to mind but it's a bit early for that), or could be a sign of a mineral deficiency. 

[Forestlens]

Isn’t it a sign of selenium deficiency? We drench regularly for it.

[silkwoodzwartbles]

Could be a cobalt deficiency, a multivitamin drench wouldn't be a bad shout.