Blackbirds in shed

A pair of blackbirds nested in my shed a few weeks ago.  I peaked in this morning and saw a wide open mouth just waiting for a food delivery so everything looks ok.  My problem is that the shed is chockablock with stuff and I’m anxious that if they can’t fly immediately it will probably land among the stuff and get hurt or perish.  Is there anything I can do to help this family?  Thanks in advance.  PS: the shed is very old and removing the accumulated junk could disturb the structure and dislodge the nest.