I've only seen effects on pups from Dwarf Hybrids that were over bred. The pups didn't act or behave different but their over all health and size were very bad when I took in a mated pair that the past owner thought they would regulate their matings. The litter they birthed for me(Her 5th in a row), almost took the Dam's life birthing cause she was so emaciated and weak. only two pups were born alive of five, and the one live pup was a Micro Dwarf who at 15 days old could sit inside a 16 oz Pop bottle cap with room to spare,
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and at 31 days required a customized small pill bottle to be a suitable tunnel.
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Here he is at 31 days walking on my desk top PC keyboard
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and a funny one which would make a very interesting looking Starwars alien
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This was him and his litter mate as Quark kissed his litter mate good-bye when his new owner took him over in Mid Indiana. You can see the HUGE size difference by 8 weeks old, which was the time it took for me to feel comfortable in allowing Quark to travel the long distance drive he had to take.
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Dubbed Tiny Tim at first he was renamed Quark(from The Star Trek Deep Space Nine series) by a gal who begged me to take him as I was too leary to even pet him out. Quark was one tough cookie and traveled from Mid Ohio to mid Wisconsin a 14 hour drive for little Quarky, but he took it all in great stride and never even missed a mealworm feast. However he had major teeth issues and required a major surgery to save his life and after that every 30 day routinely teeth trims at the Vets to assure he would be able to live as normal a life as a Micro Dwarf can live. He actually reached 3 years old before peacefully curling in his mistresses hand and leaving this world for the Final Frontiers.