So so sorry, Evie. Certainly understand your sadness. You & your blues have really been through it! The good news is that they never give up!
FYI- I have a bluebird friend that has had multiple rat snake attacks & no baffle has kept them from getting to eggs or babies (box far from trees, fences, etc.). She finally had to put a Krueger guard on her pole. Tried to get her to consider Noel guard, but she said these snakes were so large that she felt the need to net the pole.