Because of course Padawan (or new Knight) Dooku is just not used to toddlers. Especially toddlers who are strong in the Force and have figured out the mind-whammy. Given that my nephew could sign for 'food', 'more', 'milk' and 'all done' at the age of 18 months, and would do it pretty emphatically, I bet searching for Jedi-candidates is one of those hell-assignments that young Knights get to season them.