When Ross is asking Chandler and Joey for their opinion about the suit he should wear, he is holding a blue suit in his right hand and a brown one in the other hand; in the next shot the suits switch places.
The crash mat is visible in the shot just before Monica falls over on her roller skates.
There is a person visible through the crack of the bathroom door just after the duck is released.
When Chandler and Joey are fighting over keeping the chick, Chandler relents and says, "I'll take her back tomorrow." Later, Joey comes home and finds Chandler and the chick watching Baywatch and says, "I thought you were gonna take her back to the store today?" However, it's still the same day. The guys are still wearing the same clothes and it's still the night of Ross's TV appearance that he misses.
When Ross asks Joey and Chandler for their opinions on which suit he should wear for his appearance on TV, he shows them a brown one and a black one but when he asks them he says brown and blue.
Joey tells Chandler his goatee makes him look like Satan. Chandler actually has a van dyke. A goatee doesn't include a mustache.
When Joey calls the pet store to ask if they sell any of the baby chicks, he says he tells them he saw them in a commercial when in fact he saw it as part of a news report on the news.