Fosco usually have 1 or 2 foals. The foals' apperance is based on the parents' apperance. Mutations are more commently passed on by the mother, and are very rarely passed on by the father. If generations go that far, they can also look like thier granparents.
Costs
Normal breeding(two of your own Fosco)=20r
Split Breeding(one of yours and one of someone elses)=10r each, permission needed from owners of both parents.
Original Split breeding(one of yours with one of mine)=15r
Wild Breeding(one of yours with a wild Fosco)=15r