the whole keeping them "company" is over rated in my opinion. generally it means that they both get a little less attention. one dog in the house is just that one dog. two dogs in the house is a zoo, so more often then not they both stay out.
when i had two dogs i was less likely to take them both places that i would have for sure taken solo dog. my dog current goes everywhere i can take him. he hangs in my truck or waits outside the bar, friends houses, or in trees. was not like that when i had two.
twice as much vet $, food $, poo to pick up, hair, stink and etc. it seems you have gotten lucky with the 1st one and her behavior, dont push your luck with a second one. get her a teddy bear, or tell her theres only room for four in the house and who goes if another dog comes on board.....
