The Kansas City Zoo has much to offer. It is very kid friendly and includes many locations where youngsters can burn off their energy, several venues where they can pet the animals. It is certainly worth a visit and you may want to take more than a day.
The orangutan mother with her babe was one of two babes I got to visit. A mama llama and her baby was also out.
The red kangaroos run free at the KC Zoo. Cool.

This map of the zoo shows two areas separated by a bold blue line. The area to the left is extremely kid friendly. Africa is on the right. The day I visited, Africa was closed as they were making major improvements.