I've always looked at breeder loans by what the person brings to the loan....

For example, say I have a Albino Pied male and my friend wants to send his het pied female to me on breeder loan. I would look at it this way:

My investment - $15k + or -
My friends investment - $2k + or -

So my friend is contributing 15% of the total value of the pairing. Therefore I would set it up so that he receives 15% of total value of the offspring. (probably a least one pied het albino or a double het or pair of dbl hets... all depends on the clutch offspring)

I would also set it up so that whomever does the actual breeding work has the first pick of the clutch.

Just an example... hope it is helpful!

Justin