Yes for stuff going into the food chain you need to keep records. You also need to be registered under feed hygiene regulations - you send an application (free) to the local council I think. Although the link below suggests you are exempt if the meat is only for your own consumption:
https://www.food.gov.uk/business-guidance/animal-feed-legislationWe have a spreadsheet which has a tab for each type of feed (quite surprising how they accumulate). Each tab has columns for name of feed, when and where bought, where stored, batch number and expiry date, date it was started and finished, what it was fed to, the related invoice/receipt and a container/sack number. When unloading feed I use a marker pen to write a number on the bag above the label, e.g. "Layers 80" on the 80th sack of poultry layers pellets, and take a photo of it on my phone. The photos are then saved in a folder on the computer with a filename the same as was is written on the sack, as are photos of the invoices.
We have a whiteboard in the barn where we write the date of starting/finishing sacks of feed - again when this is full I snap a photo and use that to update the spreadsheet.
Much easier for me than cutting out labels from sacks (here they are all stickers applied to the bag) and faffing about with physically storing them somewhere.
If nothing else having these records helps with planning and budgeting. I can work out how much the chickens are eating for example and use that to cost out egg production, or use last years hard sheep feed use to estimate how much we'll need this year for a bigger flock.