I have a revised post of a "homemade creep feed gate" that I posted on 4/26/2017.
This is our homemade creep feeder, it has worked out well for our first attempt at making one.
If I were to make another one, I would just make it bigger, more room for the lambs when they are in it
also if the ewes attempt to put their head through, with it larger in diameter they wouldn't be able to reach the feed pan. The slots in this one are large enough that some of the ewes can get their heads in, but I want the slots big enough to accommodate the lambs as they grow.
Therefore, a completely larger creep feeder would keep the ewe's out completely.