Not a tree boa, but here is a paulsoni female eating a chick.

Chicks are cheap (cheaper than rodents) and readily available. I supplement many of my snakes' diet with avian prey with good results. However, I prefer a varied diet for most species so i wouldn't use birds as an exclusive diet, particularly for Candoia.
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B. W. Smith
Animal South
www.reptileeducation.com
www.indigosforever.org