CRA has many rules involving Shared Custody, and most of the credits cannot be "split". 

• If you are referring to the Canada Child Benefit, the requirements and application are completed separately from your tax return. The only information CRA takes from the tax return is your income. CRA Information - CCB and Shared Custody
• For determining the Eligible Dependant Amount, you and the other parent must decide which one is going to claim this credit. Many parents use alternating years, but keep in mind that if you cannot agree on who claims the credit, CRA will disallow the amount for both. 
  • Certain rules apply when one or both parents are required to pay support for the child and more information can be found here: Child custody and the amount for an eligible dependant.
• If you are claiming Childcare and Medical Expenses, you will need to enter the details of the dependant in TurboTax in order to be able to claim these expenses for that particular dependant. Only enter any expenses you actually paid and  be sure you answer any questions in regards to the Eligible Dependant Amount correctly so you do not receive a credit you are not entitled to.