how can I clean chickens in Sims 4

@michelle112 

There is an option on the chicken coop to clean it.  Once the coop is clean, the chickens will be clean the next time they go in and leave it.  I'm not sure that there is another sprinkler if you don't have Seasons.  I think the one that comes in that pack is the only one.  But you don't need the sprinkler to clean the chickens.  It is only used for watering plants in your garden.

Hope this helps.

@michelle112

If you have a good relationship with your chickens then eventually you can get a social interaction with them to discuss Preening. Once you do that then the chickens have good satisfaction levels they will preen and clean themselves. You should keep their coop clean as well.