You can bulk update default pick locations across multiple SKUs by populating a spreadsheet in the below format and uploading it.
Uploading Picking Locations in bulk
To upload a bulk file of default pick locations:
1. Navigate to Settings, then scroll down to warehouses and select Upload Bulk Warehouse Spreadsheets
Inventory Record Must Exist!
In order to set a new default location, an inventory record must already exist for the product
2. Download the template provided:
3. Complete the template as per this example
If you don't want to transfer any unassigned stock then set to FALSE
4. Save the file once completed. Then navigate to the upload section - select 'DefaultPicking', browse to your file and press Upload.