I don't see a problem with a mother hen and chicks eating medicated feed.
Most feed Co.'s will use one of two types of medications as a active ingredient in there medicated poultry feed one type is Amprolium which goes by the trade names Corid and Amprol and is a thiamine analog, competitively inhibits the active transport of thiamine (B1).
The second type of medication used is Lasalocid and goes by the trade name Bovatec. Bovatec (lasalocid) is a coccidiocide that kills coccidia. It is an ionophore that moves potassium, sodium, calcium and magnesium into the cell causing the cell to burst. Bovatec works primarily on a single developmental stage of coccidia, providing a more narrow range of action than Deccox.
You can feed medicated poultry feed to adult fowl but it is best not to eat the eggs wile the hen is being fed medicated poultry feed and for up to a week after.
Chris