whats the joke
It's the store's name. "Sneed's feed and seed (Formerly Chuck's)"
The joke here is that it used to be chucks. But it wouldn't be "Chuck's feed and seed" because of the eed.
Note that Sneed and Chuck both have 5 letters in them
Take the last 3 letters out and you get eed and uck
Replace the 3 last letters of feed and seed with uck, and you get forget and suck.
Therefore, it was formerly named "Chuck's forget and suck"