My pen is really muddy,we have had a ton a rain. Can I put grass clippings in it ? They seem to like it when I throw a handful in,but a co-worker told me they cant have clippings from a mower,it will kill them(gas fumes). What else can I put in the pen until it dries up so they don't have wet feet all the time ? I always thought they could eat grass,dig in leaves and suc. TY
		
		
	 
Upon what does your co-worker base his knowledge about gas fumes in grass clippings?  I have a lawn which covers about 1 acre.  Hubby has been using a bagger for a number of years.  A lot of those clippings go in the coop and run, and in the grow out coop (which is a favored hang out).  The rest get used in sheet composting and in the garden.  Last weekend, hubby mowed the lawn and dumped 4 bags of clippings in the chicken run.  The flock had been out to free range all day, but when he dumped those clippings, half of the flock came running back into the run to eat the clippings, when they could have been eating fresh grass!  Obviously, they did not get the memo that grass clippings are contaminated with gas fumes and will kill them.  Or, perhaps they like the extra seasoning imparted by the fumes.  
As for your muddy run, I would start to turn it into a deep litter run right away, unless it's a short run without enough height to make that feasible.  A mixture of hay, spent coop litter, leaves, grass clippings (with or without the gas fumes 

), garden debris, AGED wood chips can all be used.  I would not use mountains of grass clippings alone, and would also get a base of dryer material down first, perhaps spread 4 - 6" of hay first, then use some of those grass clippings.  A deep layer of grass clippings, especially used over wet ground will turn into a moldy, slimy, anaerobic mess.  And... that possibly could make your chickens sick.  But, spread out so it gets a chance to dry, those grass clippings will be a wonderful addition to your deep litter.  (goal would be to make that DL about 6" deep.)
One other consideration:  do you have a drainage problem where your run is?  While a lot of rain will make the ground soggy, you should do an assessment to be sure your run is not sitting in a low spot, or that it is not collecting water from a roof or gutter system on your property.  Sometimes an area needs to be trenched or the run area needs to be built up.  An other option would be to put a metal roof over the run to divert rain away from the run.  The roof would also provide needed shade.  If you build a roof, be sure it can deal with your snow load, if that is an issue where you live!