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    <issuer>
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        <issuerName>TYSON FOODS INC</issuerName>
        <issuerTradingSymbol>TSN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001552992</rptOwnerCik>
            <rptOwnerName>Hayes Thomas P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2200 W. DON TYSON PARKWAY</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SPRINGDALE</rptOwnerCity>
            <rptOwnerState>AR</rptOwnerState>
            <rptOwnerZipCode>72762</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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            <isOfficer>1</isOfficer>
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            <isOther>0</isOther>
            <officerTitle>President and CEO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

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            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
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                    <value>24609.0</value>
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                <transactionAcquiredDisposedCode>
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            <exerciseDate>
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            </exerciseDate>
            <expirationDate>
                <value>2027-11-17</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
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    <footnotes>
        <footnote id="F1">Represents shares of the Issuer's Class A Common Stock received by the Reporting Person pursuant to the Issuer's dividend reinvestment plan since the last Statement of Changes in Beneficial Ownership was filed by the Reporting Person.  Such acquisitions are exempt from Section 16 concurrent reporting requirements pursuant to Rule 16a-11.</footnote>
        <footnote id="F2">Includes 7,952.3386 shares of Class A Common Stock which vested as described in footnote 5; 47,814.9497 shares of Class A Common Stock which vest on July 1, 2018 if the performance metrics described in the applicable Stock Incentive Agreement are achieved; 8,634.783 shares of Class A Common Stock which vest on December 1, 2018 if the performance metrics described in the applicable Stock Incentive Agreement are achieved; and 7,354.251 shares of Class A Common Stock which vest on November 18, 2019 if the performance metrics described in the applicable Stock Incentive Agreement are achieved.</footnote>
        <footnote id="F3">On November 21, 2014 the Reporting Person received a grant of 24,609 performance shares which vested (in whole or in part) or expired on November 17, 2017 subject to the achievement of performance criteria in the applicable Stock Incentive Agreement. The performance criteria were (a) a cumulative adjusted earnings before interest and taxes (EBIT) target of $8,704 million for the 2015-2017 fiscal years and (b) a favorable comparison of the Issuer's Class A common stock price relative to the stock prices of a predetermined peer group of publicly traded companies over the 2015-2017 fiscal years. The performance shares could vest at a level of 50%-200% and were previously reported as derivative securities at the 200% level. On November 17, 2017, 21,950.648 shares vested and are reported herein as acquired non-derivatives securities.</footnote>
        <footnote id="F4">Pursuant to an election made by the Reporting Person, 10,018 shares were sold by the Reporting Person to the Issuer on November 17, 2017, to satisfy tax withholding obligations related to the vesting described in footnote 3.</footnote>
        <footnote id="F5">On November 17, 2017, 7,952.3386 shares of restricted Class A Common Stock vested. These shares were previously reported as beneficially owned by the Reporting Person. Pursuant to an election made by the Reporting Person, 2,724 shares were sold by the Reporting Person to the Issuer on November 17, 2017, to satisfy tax withholding obligations.</footnote>
        <footnote id="F6">Includes 47,814.9497 shares of Class A Common Stock which vest on July 1, 2018 if the performance metrics described in the applicable Stock Incentive Agreement are achieved; 8,634.783 shares of Class A Common Stock which vest on December 1, 2018 if the performance metrics described in the applicable Stock Incentive Agreement are achieved; and 20,644.945 shares of Class A Common Stock which vest on November 18, 2019 if the performance metrics described in the applicable Stock Incentive Agreement are achieved.</footnote>
        <footnote id="F7">Award of Class A Common Stock which vests on November 13, 2020 if the performance metric described in the applicable Stock Incentive Agreement (the Incentive Agreement) are achieved and the Reporting Person is employed by the Issuer on the vesting date. The performance metrics are achievement of a three year (fiscal 2018-2020) cumulative EBIT target as set forth in the Incentive Agreement.  If the performance metric is not achieved, the award expires.</footnote>
        <footnote id="F8">Includes 47,814.9497 shares of Class A Common Stock which vest on July 1, 2018 if the performance metrics described in the applicable Stock Incentive Agreement are achieved; 8,634.783 shares of Class A Common Stock which vest on December 1, 2018 if the performance metrics described in the applicable Stock Incentive Agreement are achieved; 20,644.945 shares of Class A Common Stock which vest on November 18, 2019 if the performance metrics described in the applicable Stock Incentive Agreement are achieved; and 17,634.988 shares of Class A Common Stock which vest on November 13, 2020 if the performance metrics described in the applicable Stock Incentive Agreement are achieved.</footnote>
        <footnote id="F9">The stock options vest at 33 1/3% on each of the first, second, and third anniversary dates of the grant.</footnote>
        <footnote id="F10">Award of performance Class A Common Stock which vests on November 13, 2020 if the performance metrics described in the applicable Stock Incentive Agreement are achieved. The performance criteria set forth in the Stock Incentive Agreement are (1) achievement of a three year (fiscal 2018-2020) cumulative EBIT target and (2) a favorable comparison of the relative total shareholder return of the Issuer's Class A Common Stock compared to a predetermined peer group of publicly traded companies over a three year (fiscal 2018-2020 ) period. Subject to the achievement of the performance criteria, the performance shares could vest at a level of 50 percent to 200 percent and are reported as derivative securities at the 200 percent level. If neither of the performance criteria is achieved, the award expires.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ R. Read Hudson by Power of Attorney for Thomas P. Hayes</signatureName>
        <signatureDate>2017-11-21</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0306
4
2017-09-19
0
0000100493
TYSON FOODS INC
TSN
0001552992
Hayes Thomas P
2200 W. DON TYSON PARKWAY
SPRINGDALE
AR
72762
1
1
0
0
President and CEO
Class A Common Stock
2017-09-19
4
J
0
1195.1833
0
A
85047.0163
D
Class A Common Stock
2017-11-17
4
M
0
21950.648
0
A
106997.6643
D
Class A Common Stock
2017-11-17
4
F
0
10018
0
D
96979.6643
D
Class A Common Stock
2017-11-17
4
F
0
2724
0
D
94255.6643
D
Class A Common Stock
2017-11-17
4
A
0
17634.988
0
A
111890.6523
D
Performance Shares
2017-11-17
4
M
0
24609
0
D
Class A Common Stock
24609.0
0
D
Non-Qualified Stock Options (Right to Buy)
77.97
2017-11-17
4
A
0
75426
77.97
A
2018-11-17
2027-11-17
Class A Common Stock
75426.0
75426
D
Performance Shares
2017-11-21
4
A
0
70539.952
A
Class A Common Stock
70539.952
70539.952
D
Represents shares of the Issuer's Class A Common Stock received by the Reporting Person pursuant to the Issuer's dividend reinvestment plan since the last Statement of Changes in Beneficial Ownership was filed by the Reporting Person.  Such acquisitions are exempt from Section 16 concurrent reporting requirements pursuant to Rule 16a-11.
Includes 7,952.3386 shares of Class A Common Stock which vested as described in footnote 5; 47,814.9497 shares of Class A Common Stock which vest on July 1, 2018 if the performance metrics described in the applicable Stock Incentive Agreement are achieved; 8,634.783 shares of Class A Common Stock which vest on December 1, 2018 if the performance metrics described in the applicable Stock Incentive Agreement are achieved; and 7,354.251 shares of Class A Common Stock which vest on November 18, 2019 if the performance metrics described in the applicable Stock Incentive Agreement are achieved.
On November 21, 2014 the Reporting Person received a grant of 24,609 performance shares which vested (in whole or in part) or expired on November 17, 2017 subject to the achievement of performance criteria in the applicable Stock Incentive Agreement. The performance criteria were (a) a cumulative adjusted earnings before interest and taxes (EBIT) target of $8,704 million for the 2015-2017 fiscal years and (b) a favorable comparison of the Issuer's Class A common stock price relative to the stock prices of a predetermined peer group of publicly traded companies over the 2015-2017 fiscal years. The performance shares could vest at a level of 50%-200% and were previously reported as derivative securities at the 200% level. On November 17, 2017, 21,950.648 shares vested and are reported herein as acquired non-derivatives securities.
Pursuant to an election made by the Reporting Person, 10,018 shares were sold by the Reporting Person to the Issuer on November 17, 2017, to satisfy tax withholding obligations related to the vesting described in footnote 3.
On November 17, 2017, 7,952.3386 shares of restricted Class A Common Stock vested. These shares were previously reported as beneficially owned by the Reporting Person. Pursuant to an election made by the Reporting Person, 2,724 shares were sold by the Reporting Person to the Issuer on November 17, 2017, to satisfy tax withholding obligations.
Includes 47,814.9497 shares of Class A Common Stock which vest on July 1, 2018 if the performance metrics described in the applicable Stock Incentive Agreement are achieved; 8,634.783 shares of Class A Common Stock which vest on December 1, 2018 if the performance metrics described in the applicable Stock Incentive Agreement are achieved; and 20,644.945 shares of Class A Common Stock which vest on November 18, 2019 if the performance metrics described in the applicable Stock Incentive Agreement are achieved.
Award of Class A Common Stock which vests on November 13, 2020 if the performance metric described in the applicable Stock Incentive Agreement (the Incentive Agreement) are achieved and the Reporting Person is employed by the Issuer on the vesting date. The performance metrics are achievement of a three year (fiscal 2018-2020) cumulative EBIT target as set forth in the Incentive Agreement.  If the performance metric is not achieved, the award expires.
Includes 47,814.9497 shares of Class A Common Stock which vest on July 1, 2018 if the performance metrics described in the applicable Stock Incentive Agreement are achieved; 8,634.783 shares of Class A Common Stock which vest on December 1, 2018 if the performance metrics described in the applicable Stock Incentive Agreement are achieved; 20,644.945 shares of Class A Common Stock which vest on November 18, 2019 if the performance metrics described in the applicable Stock Incentive Agreement are achieved; and 17,634.988 shares of Class A Common Stock which vest on November 13, 2020 if the performance metrics described in the applicable Stock Incentive Agreement are achieved.
The stock options vest at 33 1/3% on each of the first, second, and third anniversary dates of the grant.
Award of performance Class A Common Stock which vests on November 13, 2020 if the performance metrics described in the applicable Stock Incentive Agreement are achieved. The performance criteria set forth in the Stock Incentive Agreement are (1) achievement of a three year (fiscal 2018-2020) cumulative EBIT target and (2) a favorable comparison of the relative total shareholder return of the Issuer's Class A Common Stock compared to a predetermined peer group of publicly traded companies over a three year (fiscal 2018-2020 ) period. Subject to the achievement of the performance criteria, the performance shares could vest at a level of 50 percent to 200 percent and are reported as derivative securities at the 200 percent level. If neither of the performance criteria is achieved, the award expires.
/s/ R. Read Hudson by Power of Attorney for Thomas P. Hayes
2017-11-21