I know that contracts can be just about what you want them to be as long as both parties agree.
I had someone approach me about using my male as a stud. I like the bitch and both of us are new to the breed and breeding. I don't care about a fee as long as my expenses are covered, and the pups have the potential to be very nice in my opinion. I couldn't keep one myself, but she planned to keep Pick. Would it be wierd for me to ask for a co-own on the Pick in lieu of any fees?
You may not be signing up for any expenses. All of that should be agreed upon IN WRITING before the breeding. I've had co-owns where we split expenses, where I do all the expenses, and many other variations, and different arrangements with two dogs co-owned with the same owner. Depends on the circumstance. Whatever the arrangement, if you can make it a win win, you've got a good one.
Also depends on what you want out of the co ownership? Do you want a future puppy or breeding rights? Spell it all out if you do it OR take a puppy and you have complete control of what you want in the future. Sometimes things on paper look better than what they really are.