When Birdie belches, Larry is standing next to her, but after he is seen behind her.
Obvious double for Moe when getting up from falling into the pan of water, and when his sister (also played by Moe) enters the room at the end.
When Birdie bites Joe on the arm, you can see the visible padding on his sleeve.
The baby colt that Moe picks up at the end suddenly jumps, causing him to be distracted by it.
When Birdie says the line, "But I can't come home with you, Joe," Moe can be seen mouthing the same line.
When Mr. Dinkelspiel is heard falling down the stairs, Benny Rubin's shadow is still seen in the background, "upstairs".
When Larry says to Birdie, "Be good and we'll take you home tomorrow, okay?," the line doesn't match his mouth moving.
Most of the dialogue when Birdie gives birth doesn't match any of the actors' mouths moving.