Jon doesn't spend all day in the stables. When he's done for the day, after finishing everything that needs to be done, or just because he's worked all day and what's left can wait until tomorrow, he goes into town, sometimes to the market, sometimes to the tavern. Just to be somewhere that isn't about horses for a few hours.

At this exact moment, he's at one of the market stalls, negotiating with the vendor over the price of a pair of boots.