We also purchased alfalfa cubes like you did. We purchased last fall so we could give them alfalfa during the winter. Since alfalfa is 16% min protein it is a great add.
The alfalfa hydrates more than expected. We add only 1 cube per 2 cups of grower pellets. However, we just hydrate the alfalfa in a separate bowl with boiling water, then add it to the pellets once hydrated about 5 min later, adding more water till it is their preferred consistency. They love wet feed, so adding in the alfalfa is an easy and nutritious add. Since we feed 20% grower pellets, they are not getting their nutrition diluted.
The alfalfa hydrates more than expected. We add only 1 cube per 2 cups of grower pellets. However, we just hydrate the alfalfa in a separate bowl with boiling water, then add it to the pellets once hydrated about 5 min later, adding more water till it is their preferred consistency. They love wet feed, so adding in the alfalfa is an easy and nutritious add. Since we feed 20% grower pellets, they are not getting their nutrition diluted.