I have broken up a number of bitch fights. I also babysit a couple of six year old girls (not generally at my house). I would NEVER want those girls to witness a bitch fight. Right now you have a girl who is maturing and is not a good candidate for living with other females. To this point, the fights have not been that serious. This can escalate, and if it does there is a danger to your child.
No, dog aggression does not mean human aggression. But when dogs are fighting, people often get bitten, usually trying to break them apart. Sometimes, a dog will bite anything else if it is pulled away from the object of its hatred. They call this misdirected aggression.
I agree that the stress level is not healthy for the dogs or the people involved. It would be much better to find a good home for one of the girls, and let your household enjoy what a dog brings to a home, a lowering of blood pressure, and a great loving companion to all the people. Right now your daughter is learning that dogs are scary. That alone would be reason enough for me to rehome one.
Jenna, RN CGC & Babs, CD RA CGC HIC
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SG3 Odessa, SchH1, Kkl1, AD
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Dolly CGC & Bear CGC