I don't know - Dr. Strazds wrote: "Do you think you can change that? Then start a campaign for the drainage system cleaners, in order to explain them their responsibility (towards this nest), to install at least 4 feeding places around the nest (each bird has its own feeding areas, which hardly overlap, and "one for each" is a too risky situation), which must have water and at least 1kg of live small fish every day. Already now."
(I have info only from the Rescue Station in Makov, CZ, but that is another situation: ... if I convert it to a one-day-old chicken, then about 10 - 12 chickens, if she eats fish, she arranges about 10 roaches with a size of 10 -15 cm)
I have info in my archive - later (but only general - how much in one nesting season)