My CS don't do them head and feetless, but the woman on the butcher counter is happy to chop them off for me (you just have to ask).
It's in their interests too because they can re-sell the bits they chop off (some people use them for soup).
The CS I go to has plenty of packaged chickens ready for roasting --- which one do you shop at??
Siglap usually. They used to do them without, but lately they all seem to be with, which is why I've asked the lady on the butcher counter in the past. Last time I had to cut the head and feet off myself it was really difficult because my knives aren't sharp enough so now I ask.
Alternatively OP, if you go to the wet market, they'll do that for you (again, they can sell the bits they cut off, so they'll be happy to do it)