How long had she been broody? I tried fostering pipping eggs to my broody who had only been broody for a week or so. After the first egg hatched, she abandoned the nest. I think that they need to be broody for close to the natural incubation period before they will switch over to "take care of chicks" mode. Also, in a natural brooding situation, the hen typically sits on her chicks for a couple of days to give the late hatching eggs an opportunity to hatch. So, she may not have set long enough, or moving her off the nest before she was ready may have upset her "mother mode". You might try sneaking them under her again tonight and see what happens. Unless she's abusing them, or abandoning them, try to let her work it out with them. Hard to do, huh?