for baby dragons, you do need to feed more often. 2-3 times a day, as many appropriate sized crickets the dragon can eat in about 5-10 minutes is fine, with quality greens left in teh cage all day long. dust one serving of crickets wtih mulitvitamine and calcium powder per day as well.
petstores often do not have proper care information available to them, often it is outdated and incorrect. what the petstore is telling you do feed your dragon is fine for an adult dragon, fed crickets 2-3 times a week with greens every day. but for a growing baby, it needs more food more often.
do a search on bearded dragon care sheets online and you will see the majority will indicate more feedings of crickets for babies than adults. also, the following books all state baby bearded dragons need to be fed more often than adults;
'the bearded dragon manual' by philippe de vosjoli stats on pg 56 for babies 2-4 months of age, 'crickets of appropriate size should be offered twice daily in amounts that are consumed in about ten minutes.'
'your bearded dragon's life; your complete guide to caring for your pet at every stage of life' by liz palika stats on pg 68, 'very young beardies [up to four months of age] grow quite rapidly and have specific nutritional needs. feed babies twice each day..'
'the bearded dragon' in the 'happy healthy pet' series, by steve grenard, stats on pg. 78, [in the side panel] 'babies need to be fed twice daily [at a minimum] during their first 6 months of life.'
also, having done alot of research on bearded dragons myself and been a regular member on these forums for 4 years or so, i have seen many places online that feeding baby dragons twice a day with crickets with salads available at all times being the standard accepted practice. many top breeders recommend the same feeding regiment and it is what they use with their own babies. the three published books are very good books to have for bearded dragon care. in some areas they do contradict eachother but for feeding, as you can see from the quotes above, all agree that dragons 6 months or younger need to be fed at least twice a day.
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PHLdyPayne