Yeah it's actually a huge pain in the ass to try to value things given that people tend to be short on both time and money. (For example, an EA probably rates a dollar going towards de-oiling a bird as negative value due to the opportunity cost, even if they feel that de-oiling a bird has positive value in some "intrinsic" sense.)

I didn't really want to go into my thoughts on how you should try to evaluate "intrinsic" worth (or what that even means) in this post, both for reasons of time and complexity, but if you're looking for an easier way to do the evaluation yourself, consider queries such as "would I prefer that my society produce, on the margin, another bic lighter or another bird deoiling?". This analysis is biased in the opposite direction from "how much of my own money would I like to pay", and is definitely not a good metric alone, but it might point you in the right direction when it comes to finding various metrics and comparisons by which to probe your intrinsic sense of bird-worth.