Running on the snow is quite a bit different than running on the bare ground. A dog needs to learn to run as fast as the conditions allow without making an excessive amount of checks. Some days are going to fool you. I have been out when I thought scenting conditions were just right and the dogs had trouble from the get go, and other days when I didn't figure they could smell anything and had them shake the leaves off the trees. But generally they need to slow down a little in the snow.
As for how old to start running, you will probably get a whole lot of opinions, but they should be running a little bit by 4 to 6 months, or a least trying to bark a little on a rabbit track by then, and well on the way to being a gundog by the time they are a year old. Just start taking them out for walks and let them learn what all the smells are and how to get around in the brush and briars. Beagles are by and large tough, smart little hounds although a little headstrong and will learn how to navigate pretty quickly. Just remember a dog that won't leave your heels will not jump many rabs for you, so let them learn that this is what you want and that it is fun. If you ever see your beagle coming at you working hard on a rab track you will swear it is grinning /ubbthreads/images/graemlins/smile.gif
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