just out the super market,, not do the birds any harm ,probably more good [as i have seen ] its a yogurt type tub,, about 80p , a couple of tablespoons in their water , re-freshed every day, as it tends to sink to the bottom of the drinker after a while ,,,tried it last year for te first time , due to buying some cocks that werereally on darkness too long [hadnt moulted a flight after last yb race, these birds fully moulted ,, well in to jan,, but completed a beautifull moult , [sometimes throwing 2 flights at a time with a third flight just half way up