<PAGE>   1
                                                                   Exhibit 10(h)




                               PURINA MILLS, INC.

                        AMENDMENT TO EMPLOYMENT AGREEMENT


       This Amendment to the employment agreement (the "Agreement") entered into
by and between Purina Mills, Inc., a Delaware corporation (the "Company"), and
Brad J. Kerbs, an individual (the "Executive"), is hereby entered into as of the
18th day of June, 2001 by and between the Company and the Executive.
Capitalized terms not otherwise defined herein shall have the meanings set forth
in the Agreement.

       WHEREAS, the Company and the Executive entered into the Agreement on
September 10, 1999; and

       WHEREAS, the Company has determined that it is imperative to encourage
the Executive to devote the Executive's full attention and dedication to the
Company in the event of any potential or pending Change in Control; and

       WHEREAS, the Company has determined that in order to encourage the
Executive to devote the Executive's full attention and dedication to the Company
in the event of any potential or pending Change in Control it is necessary to
amend the Agreement; and

       WHEREAS, the terms of this Amendment were approved by the Board of
Directors of the Company on May 25, 2001 and June 17, 2001.

       NOW, THEREFORE, in consideration of the premises and mutual covenants in
this Agreement, and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties hereto agree as
follows:

                                       I.

       Section 1(m) of the Agreement is hereby amended by inserting the
following at the end thereof:

       "; PROVIDED, HOWEVER, that in the event of a Change in Control, "Term"
       shall mean a period commencing on the date of the consummation of the
       Change in Control and continuing until the second anniversary of such
       date."

                                       II.

       Section 2.1 of the Agreement is hereby amended in its entirety to read as
       follows:

              "2.1 INITIAL TERM OF AGREEMENT; RENEWAL TERMS. Subject to Section
       2.2 of this Agreement, the initial Term of this Agreement shall be for
       two years commencing on the Effective Date, subject to automatic renewal
       for a Term of an additional one


<PAGE>   2


       year commencing immediately upon the end of the initial Term or the
       then-current renewal Term, as the case may be, unless either party to
       this Agreement gives Notice of Non-Renewal to the other party not less
       than 90 days prior to the end of the initial Term or the then-current
       renewal Term, as the case may be; PROVIDED, HOWEVER, that in no event may
       the Company give a Notice of Non-Renewal to be effective on September 10,
       2001. In the event that a Notice of Non-Renewal is timely given as set
       forth in this Section 2.1, the Term of the Agreement will end on the last
       day of the initial Term or the then-current renewal Term, as the case may
       be, but the employment of the Executive will continue with the Company on
       an "at-will" basis."

                                      III.

       Section 2.2 of the Agreement is hereby amended by deleting the phrase
"Notwithstanding Section 2.1" where it appears therein and inserting the phrase
"Notwithstanding Sections 2.1 and 2.2" in place thereof.

                                       IV.

       Section 2 of the Agreement is hereby amended by redesignating Section 2.2
of the Agreement (as amended above) as Section 2.3 and by inserting the
following new Section 2.2 immediately after Section 2.1 of the Agreement:

              "2.2 EFFECT OF AGREEMENT IN THE EVENT OF A CHANGE IN CONTROL.
       Notwithstanding anything in this Agreement to the contrary, in the event
       of a Change in Control (a) the Term shall automatically be extended until
       the second anniversary of such Change in Control, (b) the Notice of
       Non-Renewal provisions of this Agreement, including, without limitation,
       Section 2.1 of this Agreement, shall no longer be effective, (c) all
       other provisions of this Agreement shall remain in effect during the Term
       (as defined in the last clause of Section 1(m)), including, but not
       limited to, the provisions of Section 4 hereof and (d) on the second
       anniversary of a Change in Control, the Term of the Agreement will end
       and the provisions of this Agreement (except for Section 5 of this
       Agreement, if applicable) shall no longer be effective, in which case the
       employment of the Executive (if not previously terminated) will continue
       with the Company following such second anniversary on an "at-will"
       basis."

                                       V.

       Section 4.7 of the Agreement is hereby amended in its entirety to read as
       follows:

              "4.7 CERTAIN ADDITIONAL PAYMENTS BY THE COMPANY. (a) Anything in
       this Agreement to the contrary notwithstanding, in the event that it
       shall be determined (as hereafter provided) that any payment (other than
       the Gross-Up Payments provided for in this Section 4.7) or distribution
       by the Company or any of its affiliates to or for the benefit of the
       Executive, whether paid or payable or distributed or distributable


                                       2
<PAGE>   3


       pursuant to the terms of this Agreement or otherwise pursuant to or by
       reason of any other agreement, policy, plan, program or arrangement,
       including without limitation any stock option, performance share,
       performance unit, stock appreciation right or similar right, or the lapse
       or termination of any restriction on or the vesting or exercisability of
       any of the foregoing (a "Payment"), would be subject to the excise tax
       imposed by Section 4999 of the Internal Revenue Code of 1986, as amended
       (the "Code") (or any successor provision thereto) or to any similar tax
       imposed by state or local law, or any interest or penalties with respect
       to such tax (such tax or taxes, together with any such interest and
       penalties, being hereafter collectively referred to as the "Excise Tax"),
       then the Executive shall be entitled to receive an additional payment or
       payments (collectively, a "Gross-Up Payment"). The Gross-Up Payment shall
       be in an amount such that, after payment by the Executive of all taxes
       (including any interest or penalties imposed with respect to such taxes),
       including any Excise Tax imposed upon the Gross-Up Payment, the Executive
       retains an amount of the Gross-Up Payment equal to the Excise Tax imposed
       upon the Payment.

              (b) Subject to the provisions of Section 4.7(f), all
       determinations required to be made under this Section 4.7, including
       whether an Excise Tax is payable by the Executive and the amount of such
       Excise Tax and whether a Gross-Up Payment is required to be paid by the
       Company to the Executive and the amount of such Gross-Up Payment, if any,
       shall be made by a nationally recognized accounting firm (the "Accounting
       Firm") selected by the Executive in his sole discretion. The Executive
       shall direct the Accounting Firm to submit its determination and detailed
       supporting calculations to both the Company and the Executive within 30
       calendar days after the termination of the Executive's employment, if
       applicable, and any such other time or times as may be requested by the
       Company or the Executive. If the Accounting Firm determines that any
       Excise Tax is payable by the Executive, the Company shall pay the
       required Gross-Up Payment to the Executive within five business days
       after receipt of such determination and calculations with respect to any
       Payment to the Executive. If the Accounting Firm determines that no
       Excise Tax is payable by the Executive, it shall, at the same time as it
       makes such determination, furnish the Company and the Executive an
       opinion that the Executive has substantial authority not to report any
       Excise Tax on his federal, state or local income or other tax return. As
       a result of the uncertainty in the application of Section 4999 of the
       Code (or any successor provision thereto) and the possibility of similar
       uncertainty regarding applicable state or local tax law at the time of
       any determination by the Accounting Firm hereunder, it is possible that
       Gross-Up Payments which will not have been made by the Company should
       have been made (an "Underpayment"), consistent with the calculations
       required to be made hereunder. In the event that the Company exhausts or
       fails to pursue its remedies pursuant to Section 4.7(f) and the Executive
       thereafter is required to make a payment of any Excise Tax, the Executive
       shall direct the Accounting Firm to determine the amount of the
       Underpayment that has occurred and to submit its determination and
       detailed supporting calculations to both the Company and the Executive as
       promptly as possible. Any such Underpayment shall be promptly paid by the
       Company to, or for the benefit of, the Executive within five business
       days after receipt of such determination and calculations.



                                       3
<PAGE>   4


              (c) The Company and the Executive shall each provide the
       Accounting Firm access to and copies of any books, records and documents
       in the possession of the Company or the Executive, as the case may be,
       reasonably requested by the Accounting Firm, and otherwise cooperate with
       the Accounting Firm in connection with the preparation and issuance of
       the determinations and calculations contemplated by Section 4.7(b). Any
       determination by the Accounting Firm as to the amount of the Gross-Up
       Payment shall be binding upon the Company and the Executive.

              (d) The federal, state and local income or other tax returns filed
       by the Executive shall be prepared and filed on a consistent basis with
       the determination of the Accounting Firm with respect to the Excise Tax
       payable by the Executive. The Executive shall make proper payment of the
       amount of any Excise Tax, and at the request of the Company, provide to
       the Company true and correct copies (with any amendments) of his federal
       income tax return as filed with the Internal Revenue Service and
       corresponding state and local tax returns, if relevant, as filed with the
       applicable taxing authority, and such other documents reasonably
       requested by the Company, evidencing such payment. If prior to the filing
       of the Executive's federal income tax return, or corresponding state or
       local tax return, if relevant, the Accounting Firm determines that the
       amount of the Gross-Up Payment should be reduced, the Executive shall
       within five business days pay to the Company the amount of such
       reduction.

              (e) The fees and expenses of the Accounting Firm for its services
       in connection with the determinations and calculations contemplated by
       Section 4.7(b) shall be borne by the Company. If such fees and expenses
       are initially paid by the Executive, the Company shall reimburse the
       Executive the full amount of such fees and expenses within five business
       days after receipt from the Executive of a statement therefor and
       reasonable evidence of his payment thereof.

              (f) The Executive shall notify the Company in writing of any claim
       by the Internal Revenue Service or any other taxing authority that, if
       successful, would require the payment by the Company of a Gross-Up
       Payment. Such notification shall be given as promptly as practicable but
       no later than 10 business days after the Executive actually receives
       notice of such claim and the Executive shall further apprise the Company
       of the nature of such claim and the date on which such claim is requested
       to be paid (in each case, to the extent known by the Executive). The
       Executive shall not pay such claim prior to the earlier of (i) the
       expiration of the 30-calendar-day period following the date on which he
       gives such notice to the Company and (ii) the date that any payment of
       amount with respect to such claim is due. If the Company notifies the
       Executive in writing prior to the expiration of such period that it
       desires to contest such claim, the Executive shall:

              (i)    provide the Company with any written records or documents
                     in his possession relating to such claim reasonably
                     requested by the Company;

              (ii)   take such action in connection with contesting such claim
                     as the Company shall reasonably request in writing from
                     time to time, including without limitation accepting legal
                     representation with respect



                                       4
<PAGE>   5

                     to such claim by an attorney competent in respect of the
                     subject matter and reasonably selected by the Company;

              (iii)  cooperate with the Company in good faith in order
                     effectively to contest such claim; and

              (iv)   permit the Company to participate in any proceedings
                     relating to such claim;

       PROVIDED, HOWEVER, that the Company shall bear and pay directly all costs
       and expenses (including interest and penalties) incurred in connection
       with such contest and shall indemnify and hold harmless the Executive, on
       an after-tax basis, for and against any Excise Tax or income tax,
       including interest and penalties with respect thereto, imposed as a
       result of such representation and payment of costs and expenses. Without
       limiting the foregoing provisions of this Section 4.7(f), the Company
       shall control all proceedings taken in connection with the contest of any
       claim contemplated by this Section 4.7(f) and, at its sole option, may
       pursue or forego any and all administrative appeals, proceedings,
       hearings and conferences with the taxing authority in respect of such
       claim (provided, however, that the Executive may participate therein at
       his own cost and expense) and may, at its option, either direct the
       Executive to pay the tax claimed and sue for a refund or contest the
       claim in any permissible manner, and the Executive agrees to prosecute
       such contest to a determination before any administrative tribunal, in a
       court of initial jurisdiction and in one or more appellate courts, as the
       Company shall determine; PROVIDED, HOWEVER, that if the Company directs
       the Executive to pay the tax claimed and sue for a refund, the Company
       shall advance the amount of such payment to the Executive on an
       interest-free basis and shall indemnify and hold the Executive harmless,
       on an after-tax basis, from any Excise Tax or income or other tax,
       including interest or penalties with respect thereto, imposed with
       respect to such advance; and PROVIDED FURTHER, HOWEVER, that any
       extension of the statute of limitations relating to payment of taxes for
       the taxable year of the Executive with respect to which the contested
       amount is claimed to be due is limited solely to such contested amount.
       Furthermore, the Company's control of any such contested claim shall be
       limited to issues with respect to which a Gross-Up Payment would be
       payable hereunder and the Executive shall be entitled to settle or
       contest, as the case may be, any other issue raised by the Internal
       Revenue Service or any other taxing authority.

              (g) If, after the receipt by the Executive of an amount advanced
       by the Company pursuant to Section 4.7(f), the Executive receives any
       refund with respect to such claim, the Executive shall (subject to the
       Company's complying with the requirements of Section 4.7(f)) promptly pay
       to the Company the amount of such refund (together with any interest paid
       or credited thereon after any taxes applicable thereto). If, after the
       receipt by the Executive of an amount advanced by the Company pursuant to
       Section 4.7(f), a determination is made that the Executive shall not be
       entitled to any refund with respect to such claim and the Company does
       not notify the Executive in writing of its intent to contest such denial
       or refund prior to the expiration of 30 calendar days after such
       determination, then such advance shall be forgiven and shall not be
       required to be repaid and the amount of any such advance shall offset, to



                                       5
<PAGE>   6


       the extent thereof, the amount of Gross-Up Payment required to be paid by
       the Company to the Executive pursuant to this Section 4.7."

                                       VI.

       Section 5.1 of the Agreement is hereby amended in its entirety to read as
       follows:

       "5.1 NON-COMPETE AGREEMENT. It is agreed that during the period beginning
       on the Effective Date and ending one year after the Date of Termination,
       regardless of whether such termination is by the action of the Executive
       or the Company or by mutual agreement, the Executive shall not, either
       for himself or on behalf of any person, firm or corporation (whether for
       profit or otherwise) engage in any form of competition with the Company,
       directly or indirectly, through any commercial venture, as a partner,
       officer, director, stockholder, advisor, employee, consultant, agent,
       salesman, venturer or otherwise, in the business of (a) developing,
       manufacturing and marketing animal nutrition products and programs for
       dairy cattle, beef cattle, hogs, horses, rabbits, zoo animals, laboratory
       animals, poultry, birds, fish and pets or (b) engaging in retailing
       operations competition with America's Country Store in the United States,
       unless such business lines are not then operated by the Company. This
       requirement, however, will not limit the Executive's right to invest in
       the capital stock or other equity securities of any corporation, the
       stock or securities of which are publicly owned or are regularly traded
       on any public securities exchange. It is also agreed that a portion of
       the severance benefits described in Section 4 hereof shall be deemed a
       payment in consideration of the non-compete provisions contained in this
       Section. The allocable portion of the severance benefits shall be
       determined by an accounting firm or valuation consultant which is
       mutually agreeable to the Company and the Executive."


       IN WITNESS WHEREOF, the parties hereto have executed this Amendment as of
the date first written above.



                                       /s/ Brad J. Kerbs
                                       -----------------------------------
Date: June 18, 2001                    BRAD J. KERBS



                                       PURINA MILLS, INC.



                                       By: /s/  Darrel D. Swank
                                          -------------------------------
                                       Name:  DARREL D. SWANK
                                       Title: Executive Vice President,
                                              Chief Financial Officer and
                                              Secretary


                                       6