listen to ganja, not medi 1, sorry medi, the curing process is a way of forcing the buds to convert the chlorophyl and the remaining starches and any remaining glucos' into more simple sugars(starch compounds) which is why cured buds look more light green to dull brownish over simply dried buds too. Remember just because the buds are picked doesnt mean they are dead, the life processes inside them go on for days, even weeks afterward and curing really just focuses those processes into what gives us the best smoke chemically speaking.
That is a little known fact, and of course is correct, but a little could be added to that, though it is not about a hay odor, just about curing. An important part of curing is to give the needed amount of time for the percentage of THC that is in a non-psychoactive form when plants are harvested and dried to become fully psychoactive, so it is also about maximizing potency and not just or mainly about flavor and odor or appearance.
The should a stem snap or bend before jarring buds question is one there is no singular answer that is correct across the board. It will depend on bud size and density and also stem size. If someone grew a sativa and has a thin fluffy bud and a thin stem and they wait for the stem to snap when bent that bud will be way over-dry. A bud like that needs to be jarred earlier/sooner when the stem bends, not breaks/snaps.
If they have a large rock solid very dense indica bud and toss it into a jar when the stem seems dry but only bends there will be a rather large amount of moisture left in the inner portion of the bud and if you do not stay on top of it and burp your jar very often you very well might lose it to mold. In cases like that a stem that actually breaks, at least to where it brakes but not like a totally dried twig but still is held together by fibers could be a better sign of when to jar.
Its something you need to become experienced at and something you need to be able to 'eyeball,' to be able to look at different crops and different buds of different types and be able to know when doing things a bit different one time or another is needed.
I pulled a bit of a joke on a friend a couple of times before letting him in on it. He was newish to growing and was having a bit of trouble drying and curing. His crops would end up over-dry and retain a hay-like odor or he would lose some or all to mold. I helped him to get the drying part down better and then I would take buds and hold them to my nose and sniff them really hard and tell him if they were still too moist or if they were ready to go into jars. He asked how I could tell if the buds were ready to be jarred or not just by smelling them and I said I am like a mule in a desert, that I can smell water. What I was really doing was putting on an act while checking bud density and stem thickness and bending the stem in a less than obvious way and together determining if they were ready to jar or not.
Two people may tell you two different ways to judge when it is time to jar and both may be totally correct .... for what they grow ... for the types of buds, sizes of buds and average density of the buds they normally deal with ... but for someone else each piece of advice that is totally correct for the one advising might be totally incorrect for the one reading/learning.
Many things about growing are carved in stone and handed down from the mountaintops and that is thee singular way of doing that particular thing correctly, but when it comes to when to jar, you really have to be able to somewhat fly by the seat of your pants.