Looking at the high quality of that seed, I'd personally plant it in a space that the chickens will get access to later on, after the "garden" is established. I wouldn't even try to sort through those seeds, just loosen the soil, scatter the seeds and give the earth a gentle toss over the seeds and see what comes up. That ought to make excellent foraging for them after it's established! The trick will be to get it firmly established before you chickens have access to it, as they will eat it roots and all if given the opportunity. If you don't have an area that you can fence off to plant these, you can build a 2x4 wooden frame with the 4" side being top to bottom, then attach hardware cloth to one side, like a picture frame, that you can lay over your planted seeds. This will give you 4 inches of growth to figure out what your next move to securing this area should be.
As for the predicament at hand; a small bag of dry cat foot smashed up with a rolling pin or moistened until soft, will cover their needs for a few days until you can get some real food for them. Cat food it typically 30% protein (a good thing for your birds), but the amino acids aren't balanced to be ideal for chickens. Moistening the food would enable you to easily 'fortify' it with canned fish (pick whatever one is cheap in your area) packed in oil (the extra calories won't hurt the chicks and the oil may have some key nutrients to offer as well).
Your dear husband spent dearly on your beloved flock... I can buy plain old scratch for cheap, dirt cheap... but then mine wouldn't be whole grain, organic luxury. Your husband is a keeper, even if he bought the wrong stuff, he was totally invested in getting your chicks 'the good stuff'.
