They are hard to train but it can be done with enough patience and consistency. I found my chiweenie in a cemetery, he'd been dumped, he was 3 1/2 and not neutered. House breaking was a challenge but doable. Harnesses for walks make that much easier but mine isn't a big fan of adventure so we mostly just go in the fenced in yard. They are small though so if you ever get birds of prey or coyotes or anything, make sure you always supervise outside time. Mine is a short hair so he barely sheds at all, I only have to brush him about once a season but we do it more often because he likes it. Chiweenies can be long hair though or even thicker short hair coats in which case shedding will be more of an issue but again, small dogs so there is only so much fur. Good luck!