We have a trick we use for the calves that wont let get close enough to put the halter. We open the halter up, put the halter on the end of a showstick, hold on to the end of the lead, slide the halter over the nose, with the extra slack you can get it over the out side ear than pull the other side over the ear closest to you with the showstick. Once the halter is on you twist the lead as you pull it tight, you twist it so the loop swings towards the calf as you tighten the halter, if you don't the loop misses the nose and you have to start over.
It usually take 2 people, one just get the calf to turn to you so you can get at his head.