Hi, Lucky1.
I would switch them over to a grower feed now. You will have to transition them for a few days by mixing the feeds. The longer they go on the higher protein feed, the stronger the chances of angel wing.
Also, this is about the time that leg problems begin to show up if your ducks are not getting enough niacin. Watch for wobbly legs, excessive sitting, unusual clumsiness walking, feet starting to turn in/overlap when they walk. If you notice this, you need to add more greens to their diet and/or add crushed up niacin pills to their feed (you want the nicotinic acid type of niacin). Even with the best of foods, some ducklings are deficient in the gut flora that converts niacin to tryptophan, so need niacin supplements, while other ducklings in the same batch may have no problems at all.
I highly suggest you purchase Storey's Guide to Raising Ducks, if your budget allows. If not, see if your local library can inter-library loan it for you. It will answer many of your questions as your ducks develop.
Hope this helps.
Tahai
