(as) happy as a pig in muck

(as) happy as a pig in muck

Very joyful and contented. Primarily heard in UK. Look at your sister out there on the field! She's happy as a pig in muck now that she's back in the team's starting lineup again. I know I'll be as happy as a pig in muck once I get this stupid cast off my leg.
See also: happy, muck, pig
Farlex Dictionary of Idioms.

happy as a pig in muck

BRITISH, INFORMAL
If you are happy as a pig in muck, you are very happy. From day one I adored it. I was as happy as a pig in muck. Note: This expression has several variations. For example, some people talk about being happy as a pig in shit. I'd much rather be as I am, I couldn't imagine being any different. Happy as a pig in shit. Frankly, I was like a pig in shit — oh, how I revelled in the opportunity of standing next to famous people!
See also: happy, muck, pig
Collins COBUILD Idioms Dictionary, 3rd ed.
See also:
  • happy as a pig in muck
  • muck
  • slop
  • (as) happy as a pig in slop
  • (as) happy as a pig in mud
  • (as) happy as a clam
  • clam
  • happy as a clam
  • happy as the day is long/as a clam/as Larry
  • Larry