Spiders can be amazingly rugged. I find tons of them inside my 1000lb. hay bales. They are in the hayfield when cut. They survive the drying/crimping, raking, acid spray preservative, and then baleing to a few thousand pounds PSI. Many of the bugs in the bales even survive the winter. I've opened a bale in february and found grasshoppers, beetles, spiders, etc... in a sort of suspended animation. They start moving once the enormous pressure is released when I open the bale.
When I had about 20 guinnea hens I hardly ever saw a single bug. They are gone now due to biosecurity measures. Soon after I noticed the Brown Recluse in our raspberry patches last season.