If a person prepared black birds before yom tov but he found white birds in the coop on yom tov, or vice versa, or if he prepared two birds before yom tov and found three birds in the coop on yom tov, the birds may not be slaughtered (because they include different birds, which had not been prepared). If he prepared three birds and found two, they are permitted (because they are presumably two of the three he prepared). If he prepared birds inside the coop and found birds in front of the coop, they are prohibited but if those are the only birds there are, they are permitted.
Beis Shammai say that one may not remove the shutters (which they used to close cabinets) on yom tov but Beis Hillel permits the shutters to be both removed and returned to their place. Beis Shammai do not permit one to cut meat using a pestle (as in “mortar and pestle”) as a cutting board but Beis Hillel permit it. Beis Shammai do not permit one to lay a hide in a place where people will walk on it (which is part of the tanning process); furthermore, they do not even permit one to carry it unless there is an olive-sized piece of flesh on it. Beis Hillel permit these things. Beis Shammai do not permit people to bring an infant, a lulav or a Torah into a public domain on yom tov but Beis Hillel permit it.