Disclaimer: This is a work in progress, but if anyone has a chance to knit this and lets me know what mistakes I make, I'd be happy to correct them.
Further disclaimer: I can design crochet patterns (I did not design the one above). I know how to knit. I'm not that great at actually knitting, but I think I can design a basic knit pattern based on the crochet pattern above from another BYC member.
I suggest using garter stitch, just to keep it simple and so it's stretchy.
This pattern is written to be cast on from back (of chicken) to front, then knit front to back and "knit back" from back to front.
Cast on 30 stitches. (This is supposed to be the length of your chicken on the underside of where the sweater is going to cover; it will go from the wish bone down, but not far enough down to interfere with walking.)
Next 7 rows:
Knit to end; knit back.
(These rows go under the chicken up to the wing.)
Next row:
Knit 7 stitches, cast off next 6 stitches, knit to end; knit back (to cast off stitches), cast on 6 stitches, finish knitting back.
(This row creates the hole for the wing.)
Next row:
Knit to end; knit back.
(This row finishes the wing hole.)
Next 3 rows:
Knit to end, add 1 stitch; add 1 stitch, knit back.
(These rows add length to cover the back of the chicken.)
Next 3 rows:
Knit to end; knit back.
(These rows go along the backbone of the chicken.)
Next 3 rows:
Knit until you have 2 stitches, knit them together; knit first 2 stitches together, knit back.
(These rows decrease back toward the row for the next wing hole.)
Next row:
Knit to end; knit back.
(This row is kind of the foundation for the next wing hole; it really just mirrors the row that finishes the wing hole on the other side.)
Next row:
Knit 7 stitches, cast off next 6 stitches, knit to end; knit back (to cast off stitches), cast on 6 stitches, finish knitting back.
(This row creates the other wing hole.)
Next 7 rows:
Knit to end; knit back.
(These rows finish the underneath of the chicken's sweater.)
Cast off.
Fold in half and sew beginning edge and ending edge together.
Please let me know how it works. =)