Unless your drying buds the size of footballs in a humid location, 2 weeks of haging is to long IME. You want to put the buds into paper bags/jars before they are bone dry, and crumbling. The key to great smelling bud is to allow the moiture to sweat out from the buds gradually.
I cut, and trim my buds when fresh. Cutting the branches off at the main stem of the plant, and hangin them to dry. In 70-73 degree temps and 30-45% humidity I let the buds dry for around 5-7days depending on size of buds, or untill I can hear a snap sound when bending the stems. The stems shouldn't be able to snap clean in half. You hear the snap of the fibers, but they should still hold enough moisture inside to bend. At that point I cut the buds from the stems, and place them into brown paper bags for a couple days, opening the bags up daily to mix the buds up so they dry evenly. After that time, when the buds have just become smokable I go ahead and place them into the glass jars for curing. I open the jars up daily as I did the bags to let out the moisture for the first week or 2, and if they feel damp to the touch I dump them out on a piece of newpaper for 5-10min or until the outside of the buds are once again dry.
With this method the scent of the varieties I grow litteraly explodes from the jars when opened, and is uncontainable in plastic Bags. Primo buds, but a liability if you gotta travel with it, or give samples to friends.
The above post is correct.I think unless you have a huge yield,your drying too long.
The other poster that wrote that they had the same problem until they started just drying the plant whole and then they had no problems.The reason for that is drying the plant whole slows down the drying process.
If your yield is a ounce or two, 5 to 7 days drying before you go to the jars.
As far as the "hay" smell.I have found that it is part of the process.That is all the nasty shit evaporating out of your product.If you continue to jar and burp without losing all the humidity so it is still curing,the hay smell will disapear and the good smell will return.
Good Luck