Equal Amounts of Stock On Stock Runs

As it stands for some restatraunts we have to go get supplies form a stockist, these always give a random amount of lettuce and venison. Could we change it so that its still random but you always get the same amount of lettuce and venison as often you'll get like 1 meat and 6 lettuce and have to go straight back to the stockist. even if we get a small amount its still nice to know we can make some food with the stock we have collected already