Easy Organic Poly method. Build a small pen with an auto turret in, set to short range and wild dinos. Put your Moschops in and then pick up Mantis and drop them in. The turret will kill them and the Moschops will harvest. I got 6000 poly in 30mins.
Feeding it what you want it to gather has NO EFFECT on its father rates. These are determined by the additional level granted every level to increase your moschops' gathering efficiency of your chosen resource.
Best for if you need fast polymer for crafting. I have used this countless times to make all the industrial equipment. But only level up health and weight and put the gathering levels into polymer. Mines at 530% and I get 50 polymer per penguin. ðŸ‘