Most common purchased breeding livestock used on farms are entered as an asset and depreciated (hogs, sheep, cattle, horses, goats). There are some exceptions. Please review IRS publication 225;
https://www.irs.gov/pub/irs-pdf/p225.pdf
If you raised the breeding stock from birth they are not entered as an asset but sold as non-depreciated business property.
Farm buildings are depreciated.
Portable panels for pens are generally expensed.
Purchased feed is an expense.