Most have names, some don't. Sometimes one will have a certain look or do something that is memorable and I'll give them a name like 'Sanchez' or 'Lonesome George', others I name after the person I got them from like 'Mike' or 'Luke' or 'Sean1', 'Sean2', 'Sean3', 'Sean4', 'Sean5' (well, you get the picture...)

No, they don't come when I call them, but it's just easier for me to refer to them by a name then by a description.