This would be a perfect example of making "alternate" agreement terms.
In lieu of "getting a puppy"...if there is not enough puppies in litter, perhaps a stud fee can then be issued, and owner of female would be responsible to pay. If single puppy...then owner & co-owner would be responsible to pay. That way...all involved are somehow compensated fairly...."maybe not ideal, but at least fair.".... JMO
Huerta Hof German Shepherds
....where breeding is still considered an art....