You need to put a feed trough in for the cow, then it will stay near that and you can fence it in for looks. Mine stays put except Codsworth keep opening the gate. LOL
Funny you say that. Last night I added several to the settlements. I haven’t really thought to look if they used them yet or not.
Since the evil that is Todd Howard has seen fit to withold the Creation Kit/Geck until 2016, I cannot bring boobs to the boobless of the wretched wasteland with my version of Lydia from Skyrim carrying my burdens, so I am forced, in the meantime, into taking out my frustration on an increasing body count of vermin ;)