Normally, when a ham comes home for the first time, they are quite nervous and/or are unsure as to whether there'll be more food.
If they are nervous, they will hoard a lot at the beginning to make sure they have a steady supply of food and don't have to come out in the open to collect more. If they are unsure as to whether there'll be a steady supply of food in the bowl then they'll hoard as much as they can to make sure they don't run out.
I find that, after a week or two, they settle down and reduce their hoards. Some are just super-hoarders though!
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Minion to Daisy, Lily, Harry and Peanut <3
Gone but never forgotten
Willow - 18:27 18th November 2016