well I have, heck in bad winters I have even feed the big bales(700-900 lbs ones)
deer will eat them, so will bears
but to be honest its much cheaper( unless your feeding the BIG bales) to use corn and corn seems to work a lot better

but yes you can use them to feed deer, they will hit them hardest in cold temps however rather than come green up when they can get it on there own by browsing fields of it!