Spoilers
“Away in the Manger”

This was the episode that was supposed to have been the crossover event with The X-Files. Apparently, David E. Kelley and X-Files creator Chris Carter had wanted to do a event involving cows and alien DNA. However, the fact was that Picket Fences was on CBS TV and The X-Files was on FOX TV and a crossover event at that time across two competing networks was just not going to work. So the great idea wound up being squashed.
However, while all the references to Picket Fences were removed from the X-Files episode (Mulder and Scully were reportedly supposed to go to Rome, Wisconsin), there were still references left in this Picket Fences episode. Carter Pike mentioned about weird things going on in Delta Glen, Wisconsin (the city where the X-Files episode was set) such as alien DNA, cows, a plane crash, and a doctor named Larsen (which are all involved in the X-Files episode).
How cool that could have been, this episode has cows giving birth to human babies. You certainly would think that Mulder would be intrigued by that.
As with all Picket Fences episodes, this main plot was used to deconstruct main characters of the show. This one was used to help look at Kimberly’s belief that there is no God as well as continuing to confuse the young Brock boys. Poor Zack has no idea what religion he is or which one he wants to partake in.

Former mayor Rachel Harris returned for this episode. She had really disappeared since losing the mayor’s office back in season two, but she popped up here as the owner of the cow and the mother of the baby boy that cow gave birth to.