Hi CaraChick Marnie,
That's a tough question Marnie, its hard to tell how much each chick eats each day. If I remember correctly from something I read a long time ago, male peregrines (which are smaller) eat between 85-100 grams/day, while females eat between 100-115 grams/day. Now these are peregrines in captivity but I haven't yet found any information on how much wild peregrines eat, but I suspect its probably about the same.
The Peregrine Chick