Find some Special Chicken Feed and return to your befriended chicken. When you find it, /cheer at it before trying to give it the Special Chicken Feed.
"Cluck... cluck... cluck... BACAW!
Cluck... cluck... cluck."
The chicken looks up at you and then starts to scratch its claws into the ground. You think it is spelling out a word, but you are not sure what it is. Could it be... S-A-L-D-E-A-N? Before you can ask, the chicken turns away and goes about its business.