Sampling hay has become more and more important, especially as the cost of supplementing poor quality forage has become less cost effective. Of course, the analysis is only as good as the technique used to obtain the sample and the tool that was used. The most frequent question that I get on this subject is "What hay probe do you recommend and where can I get one?"
I personally use the Penn State Sampler for my day-to-day use, and I purchased it through NASCO (see here for a direct link to their page for this hay probe). I recommend this probe to our County Extension Agents and for instances when only a few bales are being sampled.
I have also used the Colorado Hay Probe and find that is the better choice for taking samples from several bales in a hay lot. If you are a commercial hay producer or a hay broker that is dealing with a large volume of hay bales and hay lots, the Colorado Hay Probe is perhaps your best choice. This probe can be purchased from Udy Corp. and perhaps at other locations that I am not aware.
My mention of these samplers does not mean that I do not recommend other types. There are a number of good probes out there. Here is a publication that some of my colleagues throughout the nation have put together in collaboration with the National Forage Testing Association. This publication lists several really good probes. They also have additional information on their website about how to select a good hay probe.