My foals are offered feed, separate to their dams, from 10 days on.
I do not like to see foals attempting to feed from their mothers buckets, as some mares, in fact most mares, are just too greedy to allow them to get anything worth having!
I also have a couple of mares that would quite happily eat their own foals rather than allow them to share.
So, mares are tied up, foals are loose and are offered a selection of feeds in an old sand tray, which is at about chest height on the foals, and made of thick polythene, so if they knock it over it cannot hurt them.
At around two to three weeks I start shutting the mares outside the round pen and feeding the foals inside.
Once they are tying up each foal has it's own, measured, feed, so I can record the amount each foal is eating.
I think it is very important to have foals, any foal, any breed, eating a good amount of feed by the time they are weaned, and this is the way I have done it for forty years. I have never over topped a foal.
You have to use your brain, of course, but I like to see my foals well made up and well fed.
Creep feeding can be dangerous for two reasons.
The first is that the biggest, most forward foal will, in all probablity, get most of the feed, while the smallest weakest foal (the one that needs the feed) will get pushed to one side.
The second is a little lighter veined- I used a creep for my first Miniature foals, 32 years ago, and came out to find Rabbits mother wedged into the creep. She had been able to get in but had then raised her head and could not work out how to get out!
She was nicknamed the "Limbo Dancer" from then on.
If however, you have only one foal, or two evenly matched foals, and the mares are not as evil as Kitty, I could see it working well.
You can get at least a couple of specially formulated for creeps, tiny pellets, for use in them.