class MyModelForm(forms.ModelForm):


    class Meta:
        model = MyModel

def __init__(self, *args, **kwargs):
    from django.forms.widgets import HiddenInput
hide_condition = kwargs.pop('hide_condition', None)
super(MyModelForm, self).__init__(*args, **kwargs)
if hide_condition:
    self.fields['fieldname'].widget = HiddenInput()
Измените поле формы django на скрытое поле