There are some great sites the kids have found to practice this science concept. Please take the time and learn more.
https://www.iknowthat.com/ScienceIllustrations/foodchains/science_desk.swf
https://coolclassroom.org/cool_windows/home.html
https://www.sheppardsoftware.com/content/animals/kidscorner/games/producersconsumersgame.swf
https://cashmancuneo.net//1games/foodchain.swf
interactivesites.weebly.com/food-chains.html
https://ecokids.ca/swf-files/gamesPage/chain_reaction.swf
https://schools.bcsd.com/fremont/4th_Sci_Life_food_chains.htm
https://www.cserc.org/sierra-fun/games/build-food-chain/