So, over this winter I have had three sources of hay to use:
1 Bought in 50% alfalfa, 50% grass (Grade 1, the hard stuff, horse Crack)
2 my own 10% alfalfa, 90% grass (nice balanced diet with a bit of fun in it)
3 Bought in 100% grass (boringly nutritious with no sugar kick at all)
Most winter I used my own hay to great success. I ran out of this a week ago and have switched to the just grass stuff. (Yes, all changes have been made gradually with a mix of both sorts fed together).
The snow has started to melt and my boys have re-found the grass that they gave up digging for in February. On thaw days they have been visibly fuller and less eager to come see my load of hay morning and night.
What I noticed while serving a buffet of mixed hay with some alfalfa in there is that they would go from pile to pile of hay looking for 'the good stuff' with alfalfa in it and would only bother with the regular grass when all the good stuff was gone.
Yesterday the snow fell again and they were hungry again. I served a full platter of grass hay with no alfalfa in it and there were tantrums all over the field as they went from pile to pile searching in vain for their alfalfa fix. Riley was charging the others away from the gator with it's load of hay because he wanted to search and find his drug of choice. In the end I went and got a slice of the 'hard stuff' and put it down for Riley just because I needed to get out of the field without fetching head collars and dealing with tantrums.
Alfalfa Sugar Addicts they surely are, and they are all going to have to go cold turkey as soon as the snow goes