How much do these yearlings weigh and what breeds are they? 1/2 a cup may have been what you decided to feed the, but it is not providing the full amount of vitamins/minerals we recommend...We'd like to see yearlings getting 1 1/2 to 2lbs of the supplement (whether 12% or 30% supplement) per day, this is the minimum feeding recommendation for these youngersters.
We are switching 12% supplement users to either 30% supplement or TC lite and since you mention they are yearlings we would recommend they get the 30% supplement at 1 1/2-2lbs a day....
Additional protein is benefical to growing/developing horses so don't be concerned with a higher protein amount. TC lite can be fed if you prefer that, but lite should be fed at the rate of 1lb per 500lb of body weight. Also know that both TC Lite and 30% supplement have a very low NSC (starch/sugar level) they are both around 9%, due to the formulation of 12% supplement it had an NSC level of 24%, it was not ideal for horses with metabolic issues while TC lite or 30% would work for these horses.
Please know that while both our supplements were named top supplements in the "Horse Journal" numerous times we decided to discontinue the 12% supplement due to lack of sales, problems with availability and often problems with keeping the product fresh at the dealer and distributor level. (It's a supplement you only had to feed in small amounts so one bag lasted a long time and the bags were not purchased in "larger" or more consistent quantities ).
We have just had higher sales of the TC Lite and 30% supplement as well.