Zoo Sensory Hour The Brandywine Zoo is offering a new series of Sensory Friendly Hours for children and guests with Autism Spectrum Disorders (ASD) and sensory processing differences.  The Zoo will open one hour early on the first Sunday of each month for our Sensory Hour and staff will modify routines and sounds to give guests a more accessible experience during their time at the Zoo. Crowds during Sensory Hours will be smaller than a typical, busy weekend day.