OK, so browsing around I came across this article...
Suitability of day-old chicks as food for captive snakes | Kevin Arbuckle - Academia.edu

At first I just assumed it meant larger snakes, (I have fed chicks to smaller boa constrictors in the past just to mix their food up a bit - variation being the key and all that!)

but this article seems to suggest that day old chicks are also a suitable food item for larger Thamnophis species....

Not sure I would try this myself, but an interesting article none the less, but then wondered if anyone had tried??