TIKA-2442, Christopher Creutzig submitted a PDF file that shows that a PDTextField can have Kids. According to the PDF spec version 1.7, table 8.69, page 675, "Kids" is (apparently) available for all fields. In the description of a Text field, the spec says
Besides the usual entries common to all fields (see Table 8.69 on page 675) and to fields containing variable text (see Table 8.71)
Acrobat is able to handle the triggering file, and when modified and saved, Acrobat maintains the parent field as a PDTextField.