[Marches Farmer]

If you stick your forefinger and thumb well into the wool and pinch up the skin to make a little tent you can direct the needle at a 45 degree angle into the bottom of the tent - that should help avoid going through the bottom of the tent and out the other side.  I don't know if it works or not but I always rub the injection site after vaccinations - seem to remember it helped when I was being vaccinated myself.

[Anke]

Actually I don't bother with the "tent", just part the wool over the shoulder with one hand and insert the needle almost parallel to the skin. It's worked so far..., but it means you usually need someone else to hold the sheep (or in the case of goats - have them secured in the head yoke on the milking stand).

[kanisha]

oops ha ha yes forgot to mention I hold my little sheeps between my knees  two hands free